What can cause a change in an object's motion?

An external force

Explanation:

Just like Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. It may be seen as a statement about inertia, that objects will remain in their state of motion unless a force acts to change the motion.

Forces

Explanation:

Many factors go into this weather its wind. collision or even friction. And this isn't really history related but ok.