Energy converted from Kinetic to ?

Question

You have two identical metal balls and push both balls with equal force down two identical tubes/tracks and both of them travel the same distance at the same speed.

Same test performed again but this time one of the tubes has a magnet which isn't directly in the path of the ball, the ball is attracted to the magnet and stops just after it is pushed.

Energy cannot be created or destroyed, only converted. So where did that kinetic energy go which was apparently 'lost' due to the ball stopping short of the others when attracted to the magnet ?

This isn't any kind of school assignment or anything like that... Just curious.

Answer 1

into your brain which then caused this question.

Answer 2

I have no Idea what you talking about (low English),but I think its converted into heat or sound or its absorbed somehow

Answer 3

The ball's kinetic energy was tranferred to the magnet and then to the earth itself. Assume for a moment that the ball was rolling in the same direction as the earth's rotation. As the ball stops its kinetic energy causes the earth's rotation to speed up since it absorbed that kinetic energy. Of course, since the earth is much more massive than the ball the change in rotational speed is so small as to be indetectable by any means we know of. If you remember the massive earthquake that caused the Boxing Day tsunami that killed all those people in Indonesia you might recall that the earth got a bit smaller because of the one tectonic plate sliding under the other. This resulted in the earth's rotational speed getting a bit faster and shortening the day by about a millionth of a second. Try to imagine how little effect your rolling ball has. Still, it does have an effect but with all the other stuff going on at the same time the effect is pretty much cancelled out.

Answer 4

Initially the ball has some KE. Now as it approaches the magnetic field of the magnet, the work done by the magnet in attracting the ball gets gradually converted into KE of ball and PE of ball in field. As such it adds to the net KE of the ball.

Now the ball collides with the magnet.

If there is friction, the ball will stop ultimately, all its energy getting converted to Heat. The ball now possesses PE due to magnetic field.

If there is no dissipative force, the ball will keep rotating at its place stuck to the magnet, all its initial Translational + Rotational KE converted to only Rotational KE now. It also has PE due to field, though

And when you remove the magnet the ball will regain its KE as the PE of ball in field now converts to KE, gradually..

Answer 5

The kinetic energy is converted into heat caused by the friction created by the interaction of the magnet acting on

the ball and tube of the system.

Answer 6

The kinetic energy is "converted" into a shock wave which is transmitted through the magnet and into the structure holding the magnet.  The shock wave then dissipates into heat in the structure and the surrounding air.

So I would say Kinetic energy into heat.

I'm not sure if a shock wave is a subset of Kinetic energy or something else!  Magnets allow the transmission of forces, like an electromagnetic motor for example.

Edit: I'm not sure that the ball would keep rotating in a fixed translational position next to the magnet, even if there was zero friction, since this would set up eddy currents in the ball?!?!?

Answer 7

The energy is converted into heat.

Answer 8

Excellent question.

In the very short-term, the energy goes into the electrical currents called "eddy currents" inside the ball and the magnet.  This principle of converting kinetic energy to electrical energy is used in the regenerative systems of electric transport, including hybrid cars.

Quite soon, however, electrical resistance converts the energy contained in these currents into heat.

Answer 9

The kinetid energy in this case remains kinetic energy.  Depending on the rigidity of the structure relative to the earth, the rolling ball and the earth have attracted each other and have each been affected.  They are moving toward each other; the ball is not only moving toward the earth.

When the ball stops, the "impact" returns both objects to nearly their original states.  There has been a small loss of potential energy by the ball which will have affected the earth.  Yes, this effect is immeasurable, but it really happened.

Answer 10

apparently its the magnetic force of the magnet with the ball lying inside its magnetic field which resulted in the ball ( preferably iron ) being attracted towards the magnet and therefore resulting in 0 velocity.

What you do say is correct i.e. if your a fan of Einstein

In this case,the kinetic velocity of the ball is too weak to overcome the force of the magnet thereby resulting in attraction

The kinetic energy hasnt vanished into thin air,its just been converted into potential energy(the capacity of the object to do work).

if you remove the magnet,the ball simply regains its kinetic motion