If you ride quickly down a hill on a bicycle your eardrums are pushed in before they pop back. Why is this?

This is due to variation bin air pressure at the two different altitudes, so air rushes out through the eustachian tube to hit the eardrum and back when u reach the ground

b) phosphorus pentoxide

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                                         : )