an object in motion stays in motion and an object at rest stays at rest unless an unbalanced force acts on it
ex: When you kick a football the force of your foot makes the ball go forward. The ball was at rest until your foot contacted the ball and sent it moving forward
an objects acceleration depends on the mass of the object and the force applied
ex: A student pushes a stack of books with a mass of 3 kg and an acceleration of 15 m/s^2. What is the force applied to the stack of books?
Answer: 45 N
every action has an equal and opposite reaction
ex: A girl is jumping on a trampoline. When she goes down and hits the trampoline the opposite force makes her bounce back up, then come back down.