What is a force which works in the opposite direction, and tries to slow an object down

Air resistance

Explanation: which is a force that tries to slow things down that are moving through air. It is a type of friction and sometimes called drag. Contact force - is a force that needs to touch an object before it can affect it (e. g. friction). Contact forces need to touch the thing that they are affecting.

Air resistance

It's friction most often called drag