# Where the energy goes?

1. Apr 23, 2013

### ParamTv

hello sir i am little confused that when we hammering a rigid wall then where the all energy goes supplied by the hammer act.
example:
suppose i am betting a wall with hammer and there is no effect on wall (mean to say wall is not moving or not creaking). Then tell me where the all energy goes in to the wall supplied by the hammer act.

2. Apr 23, 2013

### mikeph

The wall is moving, you just can't see it. Whatever kinetic energy is not conserved will be converted to heat and sound in the hammer/air/wall.

3. Apr 23, 2013

### CWatters

If the hammer bounces off the wall then some is still in the hammer.

4. Apr 23, 2013

### Danger

Also, a lot comes back into your own body in the form of vibrations.

5. Apr 23, 2013

### Staff: Mentor

Sometimes it helps to think of extreme situations.

If the wall is made of soft clay then when you hit it with a hammer the hammer will "thud" into the wall. In that case the KE of the hammer goes into deforming the wall and the hammer stops.

On another extreme if the hammer is made of rubber then the hammer will "bounce" off of the wall. In that case the hammer changes direction but keeps the KE approximately the same overall.

Hopefully you can think of your situation in the context of those extremes.

6. Apr 23, 2013

### Staff: Mentor

If you've ever used a needle gun(a bunch of little jackhammers), they get extremely hot due to the repeated impacts.