Question

drag the missing word into place
first, an object at rest stays at rest, of course,
unless there’s an outside
so the pushing, the pulling, determines the speed,
like sticks hitting pucks in a rough game of hockey.

Explanation:

This is related to Newton's First Law of Motion, which states that an object at rest remains at rest, and an object in motion remains in motion with a constant velocity, unless acted upon by an external force. The context here (pushing, pulling, sticks hitting pucks) refers to a force being applied. So the missing word should be "force".

Answer:

force