FORCE AND MOTION

NEWTON’S LAWS OF MOTION - Established the relationship between motion and force

FIRST LAW – LAW OF INERTIA Every object tends to remain at rest or move with a constant velocity unless acted upon by a net force. NET FORCE – summation of all forces acting on a given body INERTIA – measure of the mass of an object Examples: a. Passenger tends to move forward when a car suddenly stops. b. A moving car in uniform motion slows down when the brake is applied.

FIRST LAW – LAW OF INERTIA This means that in theory an object can travel FOREVER. However, in practice there would always be some friction to slow it down. v v

Force is either a push or pull

SECOND LAW LAW OF ACCELERATION The acceleration (a) of a body is directly proportional and in the same direction as the net force (F) applied to it and inversely proportional to the mass (m). a (m/s2) = Force (kg-m/s2) mass (kg) Unit of force = 1 newton (N) = kg-m/s2

SECOND LAW LAW OF ACCELERATION m

SECOND LAW LAW OF ACCELERATION m An increase in force will produce an increase in acceleration.

SECOND LAW LAW OF ACCELERATION m An increase in mass will produce less acceleration (for the same amount of force).

THIRD LAW LAW OF INTERACTION For every action, there is an equal but opposite reaction. When a force is applied to an object, the object exerts a force that has the same magnitude but opposite in direction. These are called action-reaction forces.

THIRD LAW LAW OF INTERACTION

THIRD LAW LAW OF INTERACTION A rocket motor A reaction force acts on the exhaust Gases gives a thrust or force on the rocket, accelerating it forward.