If there is no friction, the force that moves the box forward horizontally must be matched by the same force.
If there is friction, then the force moving it forward = frictional force + the additional force you need to add.
Answer:
Depends on what pole it is.
Explanation:
If the poles of the cars and magnets are the same they will repel, if different, attracts.
d. the rate at which work is accomplished
"Multiple accelerations" is a puzzling phrase, and I'd be curious to understand it
better. Sadly however, you haven't explained it at all.
If the multiple accelerations are the accelerations of multiple objects, then
the net force on each object is the product of (its mass) x (its acceleration).
If the multiple accelerations are the acceleration of one object at different times,
then at any instant of time, the net force on the object is the product of (its mass) x
(its acceleration at that instant).