True or false: There is only one possible choice of system which could be correct when doing problems using work and energy.

How would a small bar magnet be oriented when placed at position x?

The movement of electrons between atoms is called an

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.