Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant

[Omnibus]

@mondrasek,

But at the end of the tracks, both balls are at the same height again.  How did the ball on the longer track get back to this height?  It had to go back UP at some point(s) along the track.  At each point it was going up it was slowing down.

It never slowed down to such an extent as to arrive at the same moment as the other ball. Its overall velocity is obviously greater and that's what matters.

[Omnibus]

@mondrasek,

And the ball gets to the end faster, but with the same exact final velocity as track #1.

That also isn't obvious, not that it matters. The ball on track #2 has had greater overall kinetic energy than the ball on track #1, obviously.

It's not about tapping into it. @Fletcher has to recognize first the obvious fact that one of the balls has greater overall kinetic energy than the other despite the fact that their initial gravitational potential energy is identical. Tapping into this difference is a separate discussion.

[Robotan]

@Omnibus

As far as I can see, friction is an important part of the equation. Static friction is greater than dynamic friction. The ball on the straight, slightly inclined, path experiences almost only static friction as it only rolls. The ball on the other track however, experiences much more free-fall, and thus more dynamic friction. Now to the key part:

Depending on what kind of friction the balls experience, they will begin to rotate. Thus the total energy of a ball at the end of a track will consist of its rotational kinetic energy + its movement kinetic energy.

The ball on the straight path gets more of the potential energy put into its rotation. The ball on the other track will not rotate as much, and will thus "move" faster.

At the end of the day, both balls "contains" exactly the same amount of energy. It is merely divided between rotational+movement.

[mondrasek]

That also isn't obvious, not that it matters. The ball on track #2 has had greater overall kinetic energy than the ball on track #1, obviously.

@Omni, no it is not obvious that both balls have the same velocity at the end of their respective tracks.  But it is, in fact, the case.  At least when I performed these experiments as required for college freshman physics labs.  The KE at the end of the tracks is exactly the same.  At certain locations along the path, one ball may have more KE than the other, but this is because it is also lower.

It's not about tapping into it. @Fletcher has to recognize first the obvious fact that one of the balls has greater overall kinetic energy than the other despite the fact that their initial gravitational potential energy is identical. Tapping into this difference is a separate discussion.

The only time the ball on the longer track has greater velocity (KE) than the ball on the straight track (at same horizontal distance from the start) is when it is LOWER than the ball on the straight track.  So it has converted MORE PE into KE at that location. 

The balls start with the same PE.  The ball on the longer track drops lower faster and so converts MORE of the available PE to KE sooner. 

At the end of the tracks, both balls have converted the same amount of PE to KE, albeit over different lengths of time.  Their velocities at the end are the same.

So the only thing we have is a greater average and instantaneous velocities (KE) on the longer track.  But at no time was a reservoir of PE converted to more KE than expected.

[Omnibus]

@mondrasek,

There's no doubt that one of the balls has more overall kinetic energy than the other although they start with the same potential energy, correct? There is no doubt therefore that one of the balls has extra kinetic energy if the entire trip is considered. If that extra kinetic energy isn't showing at the end of the trip then it has to have been converted into something else along the way. The fact remains, however, that the ball with the extra kinetic energy arrives sooner than the other ball. Therefore, it hasn't been converted into any other form of energy (hasn't been lost) but is indeed used to bring the ball sooner at the end point even though, in addition, the path is longer. Thus, either your freshman physics experiment has to be re-done more carefully or there is an explanation other than the ball being lower when having higher KE--if the increase in KE were only because the ball gets lower then it would've been exactly compensated when the ball gets back higher and we won't see it arriving earlier than the other ball at the end point.