2 Balls on slope, one is faster...

[hartiberlin]

Hi All,
please have a look at this:

http://faraday.physics.uiowa.edu/mech/1D15.50.htm

Movie :

http://faraday.physics.uiowa.edu/movies/MPEG/1d15.50.mpg

Please let me know, why the ball which goes lower is faster at the end
and leaves the slope faster.

Does it have more kinetic energy ?

Or is the ball on the upper slope just having more friction, so
it is slower at the exit ?

What do you think ?
As the balls have the same potential energy at the exit,
the kinetic energy should be equal regarding the energy laws...

Regards, Stefan.

[PaulLowrance]

Dear Stefan,

It is not going faster.  Both balls end at the same speed.  I just used calipers to measure the velocity from frame to frame at the very end.  As far as I can tell on video they are traveling the same velocity in the end.  Of course if you had high speed measuring devices you'll notice a slight difference just because of friction differences in the fall and rise.

Traveling from Point A to Point B in a faster time does not require more energy.  The reason the front ball gets there faster is because it accelerates to a faster speed as it converts PE to KE. Therefore the ball is traveling at that higher speed for the entire length of the bottom part of the track.  Then it slows back to normal speed when it climbs back up the ramp as it converts KE back to PE.

Paul

Hi All,
please have a look at this:

[/url]http://faraday.physics.uiowa.edu/mech/1D15.50.htm[/url]

Movie :

[url]http://faraday.physics.uiowa.edu/movies/MPEG/1d15.50.mpg[url]

Please let me know, why the ball which goes lower is faster at the end
and leaves the slope faster.

Does it have more kinetic energy ?

Or is the ball on the upper slope just having more friction, so
it is slower at the exit ?

What do you think ?
As the balls have the same potential energy at the exit,
the kinetic energy should be equal regarding the energy laws...

Regards, Stefan.

[terry5732]

The ball traveling the longer distance has a shorter(edit) SECOND  bounce in the movie i watched. And it would reason to have less energy as it had longer friction contact.

[hartiberlin]

No, I watched the movie in single stepby step and it seems both bounce on the table at the same
distance from the ramp! Also somewhere in the article it was said, that with measuring with
carbon black paper you can actually see where they bounce onto the table and that the
distance is equal.

Now it seems, how can we use this principle that the one ball runs faster to generate
somehow a difference voltage ?
Maybe slowing the balls down ins some magnet-electromagnet arrays to induce a voltage ?
But then the faster one must already be  generating more voltage than the slower one
and somehow both must adds up and the balls must also be again accelerated from it...

Hmm...

Regards, Stefan.

[PaulLowrance]

Now it seems, how can we use this principle that the one ball runs faster to generate
somehow a difference voltage ?

Both balls are going the ~same speed at the end.