Relative motion can best be defined as B<span> the motion of one object as it appears to another object.
An example is when you are in a car the car has the actual motion because it is the one moving but you are also moving because of relative motion.</span>
Of the forces listed I think the force of him diving and sliding across the infield acted on the player.
I think so because the slowing down was a result of an action, and I don’t think that should count as An action when it is the result of an action. However, the act of diving head-first into second base and sliding across the infield are independent actions and will cause friction, which will act upon the player.