A ball thrown vertically upward reaches a certain height and comes down again. What can you say about its kinetic energy at the maximum height?

Question

shane_b · Answer

Ok, at its max height, what is its velocity?

anonymous · Answer

9.8?

shane_b · Answer

No, that's acceleration due to gravity.  At the top of its flight its velocity is 0 for an instant just before it changes direction.  $$KE=\frac{1}{2}mv^2$$Therefore its KE is 0 at that point.  Its potential energy (PE=mgh) is at maximum at that same point.

Basically it works like this: On the way up all of its KE is converted to PE (as it loses upward speed) and on the way down all of its PE is converted to KE (as it gains downward speed).

anonymous · Answer

Shane_B its like  "hmmm i ll ask you one question.. if you don't answer this right.. i ll tell the whole answer myself " lol :D

shane_b · Answer

I have no self control :/

anonymous · Answer

lol :D.. self control is important man :O.. could get you into trouble :O