Help quick!! Only answer!
I don't need explanation.
A body created an echo near a well of depth 18m
What is the maximum height to be reduced so that he can hear the echo at 0°c
What is the time for him to listen to the echo at 20°c

17.2 m.

Explanation:

answer: good job it's all correct !

explanation:

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )