What do we call it when two or more moving objects exert forces on each other for a short period of time?

It is called a collision.

Explanation:

When two objects bump into each other, this is called a collision. In physics, a collision doesn't have to involve an accident (like two cars crashing into each other), but can be any event where two or more moving objects exert forces on each other for a short period of time.

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.