In the illustration, which two simple machines are being used to enable the student to reach the door?

a)
inclined plane and pulley

b)
lever and wheel-and-axle

c)
pulley and lever

d)
wheel-and axle and inclined plane

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                                         : )

mass and volume are the answers you are looking for