How can density be used to describe Earth’s Layers?

Earth has layers because of density. Dense materials such as iron sank to the middle of the Earth, the center of its gravity. Less dense materials stayed at the top.

pe = weightxheight = 2000x1000=2,000,000joules

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                                         : )