Question

ANY help with answering ANY of the questions would be greatly appreciated. I don't understand physics at all.

Answer 1

12) 16 m/s (Law of Conservation of Momentums) 
13) 12 lbs (don't worry that you do not understand physics, your teacher do not understand it as well, force is not measured in kg or lbs) 
15) 15N and direction opposite to force applied initially
16) 19m