The physical principles that describe the behavior of objects in motion and at rest are encapsulated in Newton's three laws of motion. Newton's First Law asserts that an object will remain at rest or continue to move at a constant speed in a straight line unless acted upon by an unbalanced force.
Ex: Newtons cradle works when one ball hits the others the ball on the end will move also.
Ex: When a cue ball hits a billiard ball the billiard ball will move forward.
For every action there is an equal and opposite re-action.
Newton's Second Law of Motion
Ex: An object moving with 2m/s times m/s and 3 kg of mass will have 6N of force.
Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car go 0.05 m/s/s. Using Newton's Second Law, you can compute how much force Mike is applying to the car by doing mass times acceleration = force.
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
Newtons First Law of Motion
Ex: A person sitting in a chair.
Ex: A golf ball sitting on a tee.
An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.