Explanation:
Newton's first law: Inertia
"An object in motion stays in motion, and an object at rest stays at rest, until acted upon by an unbalanced force."
This means that an object does not speed up, slow down, or change direction, unless the forces acting on it are unbalanced.
Newton's second law: Net force
∑F = ma
The net force (the sum of the forces acting on an object) is equal to the object's mass times its acceleration.
Newton's third law: Action/reaction
"For every action, there is an opposite and equal reaction."
This means that when one object pushes on another object (action), the second object pushes back with an equal and opposite force (reaction).