Easy verification of F=ma on an airtrack

[Dave]

Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.

To verify F=ma, with kinetic energy E =1/2 mv^2

Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel. The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

So if you have up to 16 springs, which all have the same stored energy
you can easily draw a graph of number of springs against final velocity,
showing the above formulas are valid.

A typical doubt can be that the acceleration in the above is speed
increase per unit distance, not time, so you end up with a linear
relationship.

[Sylvia Else]

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.
So if you have up to 16 springs, which all have the same stored energy
you can easily draw a graph of number of springs against final velocity,
showing the above formulas are valid.
A typical doubt can be that the acceleration in the above is speed
increase per unit distance, not time, so you end up with a linear
relationship.

Your experiment, even if you performed it, would be incapable of
distinguishing between the Newtonian formula E=1/2mv^2 and the
relativistically corrected formula, which, for v << c, gives the almost
the same result, with a difference too small to be measured.

That is, the experiment verifies, within the limits of measurement, both
theories, giving you no way to choose between them.

Sylvia.

[Dave]

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m
of travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.
So if you have up to 16 springs, which all have the same stored energy
you can easily draw a graph of number of springs against final
velocity, showing the above formulas are valid.
A typical doubt can be that the acceleration in the above is speed
increase per unit distance, not time, so you end up with a linear
relationship.

Your experiment, even if you performed it, would be incapable of
distinguishing between the Newtonian formula E=1/2mv^2 and the
relativistically corrected formula, which, for v << c, gives the almost
the same result, with a difference too small to be measured.
That is, the experiment verifies, within the limits of measurement, both
theories, giving you no way to choose between them.
Sylvia.

Thank you for your reply, but this is well below relativistic speeds,
e.g. 1kg, with 1N springs and an airtrack costing about USD 2000.

Add energy incrementally (more springs/bands), and check the speed goes
up as the square root of the energy added.

If you do the sums is quite a difference between "common sense" and what
the formulas predict.

With four springs, the difference is two times.
With 16 springs, the difference is times four.

And because the difference would be a gain, it can't be explained away
as a loss.

With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

[Jim Pennino]

In sci.physics Dave <***@yahoo.com> wrote:

<snip>

Post by Dave
With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

These formulas, which you do not understand by any stretch of the
imagination, have been tested and verified more than a few times in the
almost 340 years since they were discovered by people who actually
understand mathematics using equipment far more sophisticated and
accurate than "ticker tape and trolleys".

[Dave]

Post by Jim Pennino
<snip>

Post by Dave
With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

These formulas, which you do not understand by any stretch of the
imagination, have been tested and verified more than a few times in the
almost 340 years since they were discovered by people who actually
understand mathematics using equipment far more sophisticated and
accurate than "ticker tape and trolleys".

Strangely enough, on Daily Mail Online, in the medical section there was
an article about how best to poo, there was a diagram of sphinters. It
was shown as a loop, not a ring as per the textbook I had for biology
101. Then there was the continental drift denying the obvious for 30
years, and the man who found out that stomach ulcers are usually caused
by infection, and type 2 diabetes CURED by a slimming fast diet. Rome
wasn't built in a day, and there are always good reasons for checking
the basics. Physics isn't about belief, it's about repeatible
experiment. In the medical world there are roots to correction, and it
is the job of many people to check common assumptions, expecially after
COVID.

[Jim Pennino]

Post by Dave

Post by Jim Pennino
<snip>

Post by Dave
With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

These formulas, which you do not understand by any stretch of the
imagination, have been tested and verified more than a few times in the
almost 340 years since they were discovered by people who actually
understand mathematics using equipment far more sophisticated and
accurate than "ticker tape and trolleys".

Strangely enough, on Daily Mail Online, in the medical section there was
an article about how best to poo, there was a diagram of sphinters. It
was shown as a loop, not a ring as per the textbook I had for biology
101. Then there was the continental drift denying the obvious for 30
years, and the man who found out that stomach ulcers are usually caused
by infection, and type 2 diabetes CURED by a slimming fast diet. Rome
wasn't built in a day, and there are always good reasons for checking
the basics. Physics isn't about belief, it's about repeatible
experiment. In the medical world there are roots to correction, and it
is the job of many people to check common assumptions, expecially after
COVID.

True, however the laws of motion have been known and tested innumerable
times over the last 340 years by innumerable people and no one has ever
found any discrepancy other than relativistic. When you count all the
high school and college classes where they are routinely done, the
number of times these laws have been "checked" is easily in the trillions.

With very few exceptions physics is pretty cut and dried it is rare in
modern times that an old theory is totally discarded and replaced by a
new theory. What usually happens is that an old theory is refined, i.e.
the laws of motion were refined for relativistic effects.

Doing physics experiments with moving objects is trivial in comparison
to doing experiments on human beings and the bulk of modern medical
knowledge is FAR more recent than the 340 years of the laws of motion.

[Dave]

Post by Jim Pennino

Post by Dave

Post by Jim Pennino
<snip>

Post by Dave
With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

These formulas, which you do not understand by any stretch of the
imagination, have been tested and verified more than a few times in the
almost 340 years since they were discovered by people who actually
understand mathematics using equipment far more sophisticated and
accurate than "ticker tape and trolleys".

Strangely enough, on Daily Mail Online, in the medical section there was
an article about how best to poo, there was a diagram of sphinters. It
was shown as a loop, not a ring as per the textbook I had for biology
101. Then there was the continental drift denying the obvious for 30
years, and the man who found out that stomach ulcers are usually caused
by infection, and type 2 diabetes CURED by a slimming fast diet. Rome
wasn't built in a day, and there are always good reasons for checking
the basics. Physics isn't about belief, it's about repeatible
experiment. In the medical world there are roots to correction, and it
is the job of many people to check common assumptions, expecially after
COVID.

True, however the laws of motion have been known and tested innumerable
times over the last 340 years by innumerable people and no one has ever
found any discrepancy other than relativistic. When you count all the
high school and college classes where they are routinely done, the
number of times these laws have been "checked" is easily in the trillions.
With very few exceptions physics is pretty cut and dried it is rare in
modern times that an old theory is totally discarded and replaced by a
new theory. What usually happens is that an old theory is refined, i.e.
the laws of motion were refined for relativistic effects.
Doing physics experiments with moving objects is trivial in comparison
to doing experiments on human beings and the bulk of modern medical
knowledge is FAR more recent than the 340 years of the laws of motion.

A year or two ago I heard on a BBC Radio 4 program that the key turning
point of disengagement from education was the ticker tape experiment.
These people turn to football or crime, or something that doesn't
involve textbooks. The educationalist said that something better needs
to be done. As a qualified, and not practiced for over 30 years,
physicist seems the level I can handle.

Either 1/2mv^2 is correct or is isn't. If it is there are better ways
to show this at reasonable cost.

If 1/2mv^2 is wrong, they powers that be aren't so stupid to have never
realised this, and teaching the wrong physics is there for a reason I am
not at liberty to speculate on sci.physics. Should issues arise with
having correct physics taught, these may need to be managed separately.

[Jim Pennino]

Post by Dave

Post by Jim Pennino

Post by Dave

Post by Jim Pennino
<snip>

Post by Dave
With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

These formulas, which you do not understand by any stretch of the
imagination, have been tested and verified more than a few times in the
almost 340 years since they were discovered by people who actually
understand mathematics using equipment far more sophisticated and
accurate than "ticker tape and trolleys".

Strangely enough, on Daily Mail Online, in the medical section there was
an article about how best to poo, there was a diagram of sphinters. It
was shown as a loop, not a ring as per the textbook I had for biology
101. Then there was the continental drift denying the obvious for 30
years, and the man who found out that stomach ulcers are usually caused
by infection, and type 2 diabetes CURED by a slimming fast diet. Rome
wasn't built in a day, and there are always good reasons for checking
the basics. Physics isn't about belief, it's about repeatible
experiment. In the medical world there are roots to correction, and it
is the job of many people to check common assumptions, expecially after
COVID.

True, however the laws of motion have been known and tested innumerable
times over the last 340 years by innumerable people and no one has ever
found any discrepancy other than relativistic. When you count all the
high school and college classes where they are routinely done, the
number of times these laws have been "checked" is easily in the trillions.
With very few exceptions physics is pretty cut and dried it is rare in
modern times that an old theory is totally discarded and replaced by a
new theory. What usually happens is that an old theory is refined, i.e.
the laws of motion were refined for relativistic effects.
Doing physics experiments with moving objects is trivial in comparison
to doing experiments on human beings and the bulk of modern medical
knowledge is FAR more recent than the 340 years of the laws of motion.

A year or two ago I heard on a BBC Radio 4 program that the key turning
point of disengagement from education was the ticker tape experiment.
These people turn to football or crime, or something that doesn't
involve textbooks. The educationalist said that something better needs
to be done. As a qualified, and not practiced for over 30 years,
physicist seems the level I can handle.

Rambling babble.

Post by Dave
Either 1/2mv^2 is correct or is isn't. If it is there are better ways
to show this at reasonable cost.

I gave you one such a way.

Post by Dave
If 1/2mv^2 is wrong, they powers that be aren't so stupid to have never
realised this, and teaching the wrong physics is there for a reason I am
not at liberty to speculate on sci.physics. Should issues arise with
having correct physics taught, these may need to be managed separately.

Kook babble.

Such has been independantly verified by millions of people around the
planet for 340 years. No one, even with the most sophisticated of
equipment, has ever found any discrepancy other than for relativistic
effects.

You are tilting at windmills and a parnoid kook if you think every
educator and scientist in every country on the planet has been "wrong"
for 340 years.

[Dave]

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m
of travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.
So if you have up to 16 springs, which all have the same stored energy
you can easily draw a graph of number of springs against final
velocity, showing the above formulas are valid.
A typical doubt can be that the acceleration in the above is speed
increase per unit distance, not time, so you end up with a linear
relationship.

Your experiment, even if you performed it, would be incapable of
distinguishing between the Newtonian formula E=1/2mv^2 and the
relativistically corrected formula, which, for v << c, gives the almost
the same result, with a difference too small to be measured.
That is, the experiment verifies, within the limits of measurement, both
theories, giving you no way to choose between them.
Sylvia.

Thank you for your reply, but this is well below relativistic speeds,
e.g. 1kg, with 1N springs and an airtrack costing about USD 2000.

Add energy incrementally (more springs/bands), and check the speed goes
up as the square root of the energy added.

If you do the sums there is quite a difference between "common sense"
and what the formulas predict.

With four springs, the difference is two times.
With 16 springs, the difference is times four.

And because the difference would be a gain against formulas, it can't be
explained away as a loss.

With verification of formulas, there is better teaching than ticker tape
and trolleys. If the formulas are wrong, then everything changes and
gets very exciting, re. dark energy, high speed travel, time and space etc.

[Sylvia Else]

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.

Sylvia.

[Jim Pennino]

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.

Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.

In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.

So far, so good.

The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.

So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.

He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.

A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).

https://www.harborfreight.com/dial-gauge-angle-finder-34214.html

For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.

For measuring velocity, several cheap methods are available and I will
describe but one:

Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.

Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.

But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

[Dave]

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Thanks, food for thought. Elastic bands are much the same as springs.

I would avoid temptation to mix in gravity directly at this stage. What
might work is something like a mini hovercraft to run over an aluminium
profile. Plus you can join them together fairly neatly for an extended
length. Also avoid anything rolling which mixes in angular momentum,
which is the whole reason airtracks were invented.

A pendulum mixes in gravity.

[Jim Pennino]

Post by Dave

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Thanks, food for thought. Elastic bands are much the same as springs.
I would avoid temptation to mix in gravity directly at this stage. What
might work is something like a mini hovercraft to run over an aluminium
profile. Plus you can join them together fairly neatly for an extended
length. Also avoid anything rolling which mixes in angular momentum,
which is the whole reason airtracks were invented.
A pendulum mixes in gravity.

Sigh.

Befuddled idiot.

[Dave]

Post by Jim Pennino

Post by Dave

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Thanks, food for thought. Elastic bands are much the same as springs.
I would avoid temptation to mix in gravity directly at this stage. What
might work is something like a mini hovercraft to run over an aluminium
profile. Plus you can join them together fairly neatly for an extended
length. Also avoid anything rolling which mixes in angular momentum,
which is the whole reason airtracks were invented.
A pendulum mixes in gravity.

Sigh.
Befuddled idiot.

Need to start with a basic conservation of energy check. No absolutes
needed, just is kinetic energy proportional to velocity or velocity squared?

F=ma doesn't apply to gyros. So obviously there is mass and intertial
mass as different things even at low speeds. Many physics says the mass
of a box is the mass as determined from the number and type of atoms.
Gross oversimplification with f=ma. You can tell if there is hidden
gyros in a box.

Am off the moving hovercraft idea, unless compressed air can be used,
any motor puts in gyro effects. Airtrack is better, you still might be
able to make one in an aluminium profile, but by the time you've done
that you'd have been better paying the money for the proper kit. For
instance you may get whistling with air coming out of holes, which
drives you up the wall.

[Jim Pennino]

Post by Dave

Post by Jim Pennino

Post by Dave

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Thanks, food for thought. Elastic bands are much the same as springs.
I would avoid temptation to mix in gravity directly at this stage. What
might work is something like a mini hovercraft to run over an aluminium
profile. Plus you can join them together fairly neatly for an extended
length. Also avoid anything rolling which mixes in angular momentum,
which is the whole reason airtracks were invented.
A pendulum mixes in gravity.

Sigh.
Befuddled idiot.

Need to start with a basic conservation of energy check. No absolutes
needed, just is kinetic energy proportional to velocity or velocity squared?
F=ma doesn't apply to gyros. So obviously there is mass and intertial
mass as different things even at low speeds. Many physics says the mass
of a box is the mass as determined from the number and type of atoms.
Gross oversimplification with f=ma. You can tell if there is hidden
gyros in a box.
Am off the moving hovercraft idea, unless compressed air can be used,
any motor puts in gyro effects. Airtrack is better, you still might be
able to make one in an aluminium profile, but by the time you've done
that you'd have been better paying the money for the proper kit. For
instance you may get whistling with air coming out of holes, which
drives you up the wall.

Rambling kook babble.

[Sylvia Else]

Post by Jim Pennino

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Thanks, food for thought.  Elastic bands are much the same as springs.
I would avoid temptation to mix in gravity directly at this stage.  What
might work is something like a mini hovercraft to run over an aluminium
profile. Plus you can join them together fairly neatly for an extended
length.  Also avoid anything rolling which mixes in angular momentum,
which is the whole reason airtracks were invented.
A pendulum mixes in gravity.

Sigh.
Befuddled idiot.

Need to start with a basic conservation of energy check.  No absolutes
needed, just is kinetic energy proportional to velocity or velocity squared?
F=ma doesn't apply to gyros.

Of course it does. Why would it not?

Sylvia.

[Dave]

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Reminds me of a video I saw which said that gyros are highly classified.
Any physics you work out is not classified, unless you're working for
that sort of employer already.

My physics course wasn't very good. No time to think, and overloaded
with disparate topics having no common thread. e.g. 200 hours of physics
lectures in the final year, and you were doing well to memorize enough
for a reasonable grade.

Pendulums are irrelevant. Gravity may be characterized incorrectly. Two
wrongs can make a right. Lots of sofware works like this, and it's a
nightmare to fix. IT consultancies love hellish code, a team gets
something a little bit working with no documentation or unit testing,
don't want to know any more, and can't explain anything, so it's left to
the integraion team to fix.

One thing at a time - check conservation of energy with 1/2 mv^2. If
this is OK, then there is the rocket sled thought experiment which needs
actualization. Since the added energy being significantly dependent on
starting speed when releasing the same chemical energy makes no sense.

[Jim Pennino]

Post by Dave

Post by Jim Pennino

Post by Sylvia Else

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel.  The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.

Why does common sense say that it goes up linearly? Even a cursory
consideration shows that the more springs you have, the more quickly
everything happens, and the less time there is for the spring force to
affect the mass. So common sense would say that the relation is unlikely
to be linear.
Sylvia.

Well, we could use Hooke's law of 1678 to analyze what happens.
Hooke's law states that the force (F) of a spring is equal to a spring
constant (k) times the displacement (x), or F=kx.
In the real world it is found that for real springs this is only a
first-order linear approximation to the real response of springs and how
close to reality it is depends heavily on the material, form and
deflection of the spring. Helical springs of spring steel over small
deflections generally follow Hooke's law very closely.
So far, so good.
The issue our nimrod hasn't concidered in using a spring to verify F=ma
is that when the spring is released the force is at a maximum with the
force decreasing as the spring expands. This means the total force
applied to the object is not F, but the intregal of the force over the
displacemnent and our nimrod can barely do algebra let alone calculus.
So if our nimrod wants to verify Newton's laws of motion he needs to
come up with a constant force small enough to keep the expriment within
the confines of something reasonable, such as a garage or patio.
He could do a little reading and discover how Galileo circa 1600
"deluted" gravity using an inclined ramp which will provide an
adjustable acceleration of gravity determined by the ramp angle.
A ramp can easily be made with a length of aluminum angle and the angle
determined by an inclinometer ($3.99).
https://www.harborfreight.com/dial-gauge-angle-finder-34214.html
For the moving object, anything spherical and smooth will do, i.e.
marbles, ball bearings, etc.
For measuring velocity, several cheap methods are available and I will
Mark the ramp or attach a tape measure and video the objects motion
with a PC at high speed and play back frame by frame and plot the data.
Once he has proved to himself that F=ma actually works, he can proceed
to prove that E=(mv^2)/2 works by building a ballistic pendulum which
was invented by Benjamin Robins in 1742.
But alas and alack nimrod will have to learn the mathematics of
pendulums to do that.

Reminds me of a video I saw which said that gyros are highly classified.
Any physics you work out is not classified, unless you're working for
that sort of employer already.

Reminds me of a doddering old fool like grandpa Simpson rambling on and
on...

Post by Dave
My physics course wasn't very good. No time to think, and overloaded
with disparate topics having no common thread. e.g. 200 hours of physics
lectures in the final year, and you were doing well to memorize enough
for a reasonable grade.

Or you were a crap student.

Post by Dave
Pendulums are irrelevant. Gravity may be characterized incorrectly. Two
wrongs can make a right. Lots of sofware works like this, and it's a
nightmare to fix. IT consultancies love hellish code, a team gets
something a little bit working with no documentation or unit testing,
don't want to know any more, and can't explain anything, so it's left to
the integraion team to fix.

Reminds me of a doddering old fool like grandpa Simpson rambling on and
on...

Post by Dave
One thing at a time - check conservation of energy with 1/2 mv^2. If
this is OK, then there is the rocket sled thought experiment which needs
actualization. Since the added energy being significantly dependent on
starting speed when releasing the same chemical energy makes no sense.

Good luck on checking conservation of energy though you might start with
Noether's theorem which states that any differentiable symmetry of the
action of a physical system has a corresponding conservation law.

[Sylvia Else]

Post by Dave
Reminds me of a video I saw which said that gyros are highly classified.
Any physics you work out is not classified, unless you're working for
that sort of employer already.

This is conspiracy nonsense. The behaviour of gyroscopes seems
counter-intuitive, but that's only because we personally have little
experience with rapidly spinning objects.

On a proper analysis gyroscopes behave exactly as predicted by the known
physical laws.

Sylvia.

[Jim Pennino]

Post by Dave
Again, there are common doubts about basic physics, easily verified by
experiment. Self consistent formulas don't convince non believers.

You mean doddering kooks?

Post by Dave
To verify F=ma, with kinetic energy E =1/2 mv^2
Have an airtrack with a 1kg mass, and a set of springs, with say 0.1m of
travel. The formulas say that the final velocity does up with the
square root of the number of springs used to put the mass in motion.
Common sense says it goes up linearly.
So if you have up to 16 springs, which all have the same stored energy
you can easily draw a graph of number of springs against final velocity,
showing the above formulas are valid.
A typical doubt can be that the acceleration in the above is speed
increase per unit distance, not time, so you end up with a linear
relationship.

A simple, cheap way to verify F=ma:

Get a WT901BLECL 3 axis sensor module available from Amazon for about
$50.

https://www.amazon.com/WT901BLECL-Accelerometer-Acceleration-Low-Consumption-Compatible/dp/B07T2C97WN

This module is 1.42 x 0.59 x 2.02 inches and weighs 30 Grams.

Among other thing, this module measures accelration in real time at a
rate of up to 200 measurements/second, is Bluetooth enabled, and has
free software for PC's and smart phones with data collection and
graphing.

Get a helical compression spring with an uncompressed length somewhere
in the order of 10-20 cm long from you local hardware store. My local
hardware store charges $5 - $10 for such springs.

Calibrate your spring by compressing it on a scale. Hooke's law says
that F=kx, so the spring constant is equal to the compressed force
divided by the compressed length. If you don't believe Hooke's law,
repeat the measurement for various compressed lengths, plot the data and
use an online Linear Regression Calculator (there are many).

Construct a cart to carry the sensor and any weights you want to use.

As the force is maximum at full compression and zero at no compression,
a track for the cart need not be any longer than the difference between
full and zero compression.

Turn on data recording on the sensor app, hold the cart against the
fully compressed spring, and let it go. Stop data recording.

Plot and analyze the data to your heart's content using the app or
download the data to online graphing and curve fitting tools.