give me an eg, where P.E, gets convere to the k.E. & IT IS CONVERTED OR brought to rest by application of p.e?

Answer 1

1.Let the system be (airplane, rubber band, Earth). Elastic PE is converted to KE, which in turn is converted to PE as the plane rises, and back to KE as it descends. Energy is transferred from you to the system when you stretch the rubber band, and from the system to the tree when the plane gets stuck.
2. Let the system be (uncle, Earth). PE is converted to KE as the uncle flops down. Energy is transferred out of the system to the couch and then to the surroundings when he lands.
3. Let the system be (ball, Earth). Only a very small fraction of the ball’s KE is converted to PE and back if the ball’s trajectory is nearly horizontal. Energy is transferred from your friend’s hand into the system when the ball is thrown, and is transferred out of the system to your mitt when you catch the ball.
4. Let the system be (cousin, swing and ropes, Earth). Energy converts back and forth between PE and KE as the swing swings (PE to KE during the downward part of the swing, and KE to PE during the upward part). Energy is transferred into the system by you with each push, and is transferring out of the system continuously because there is friction between the rope and the supports.
5. Conversions include: elastic PE to KE when spring is released, radiated energy to internal energy (this is microscopic; we’ll have to say more about it
later) when the sun warms everything, PE to KE as the hammer descends, internal energy to radiated energy when the rope bursts into flame giving off light, electrical PE to KE (of the fan blades) when the fan is turned on. Energy is transferred from: the spring to the block, from the sun to everything it warms, from the hammer to the fan button (this energy is dissipated – that is, it is in turn transferred to the surroundings), from the outlet to the fan (this is the energy that makes the fan go), and from the fan blades to the air (a transfer of KE).

Answer 2

a swinging pendulum

at the top of its swing, it has only PE (mgh) and at the bottom, it has only KE (1/2mv^2), but when it reaches the other side, it's back to stricly PE.