A 2 kg rock is released from rest at a height of 29 m. Ignore air resistance and determine the kinetic energy, gravitational potential energy, and total mechanical energy at each of the following heights;20m 15m 9m

Question

* physics - bobpursley, Wednesday, November 17, 2010 at 9:32am

PE= mgh at any height.

KE at any height= InitialPE-finalPE
Total mech energy = KE+ PE

Please Can you explain how I can calculate kinetic energy if I don't know velocity I know formula mv^2/2 in this case I have to know the velocity.

Answer 1

if KE = energy lost in PE

and you fell x distance, then

1/2 mv^2=mg*x and you calculate v from that.