WELCOME

BackgroundSir Isaac Newton (1643-1727) an English

scientist and mathematician famous for his discovery of the law of gravity also

discovered the three laws of motion. He published them in his book Philosophiae

Naturalis Principia Mathematica (mathematic principles of natural

philosophy) in 1687. Today these laws are known as Newton’s Laws of Motion and describe the motion of all objects on the

scale we experience in our everyday lives.

Newton’s Laws of MotionNewton’s Laws of Motion

• 11stst Law Law – An object at rest will stay at – An object at rest will stay at rest, and an object in motion will stay rest, and an object in motion will stay in motion at constant velocity, unless in motion at constant velocity, unless acted upon by an unbalanced force.acted upon by an unbalanced force.

• 22ndnd Law Law – Force equals mass times – Force equals mass times acceleration.acceleration.

• 33rdrd Law Law – For every action there is an – For every action there is an equal and opposite reaction.equal and opposite reaction.

third law: For every action force, there is an equal and opposite reaction force. (Forces are always paired)

33rdrd Law Law

According to Newton, According to Newton, whenever objects A whenever objects A and B interact with and B interact with each other, they exert each other, they exert forces upon each forces upon each other. When you sit in other. When you sit in your chair, your body your chair, your body exerts a downward exerts a downward force on the chair and force on the chair and the chair exerts an the chair exerts an upward force on your upward force on your body. body.

33rdrd Law Law

Flying gracefully Flying gracefully through the air, through the air, birds depend on birds depend on Newton’s third Newton’s third law of motion. As law of motion. As the birds push the birds push down on the air down on the air with their wings, with their wings, the air pushes the air pushes their wings up their wings up and gives them and gives them lift.lift.

Examples of Newton’s 3rd Law

a)rockets leaving earthb)guns being firedc) two cars hit head on d) astronauts in space e) pool or billiards f) jumping out of a boat onto the dock g) sprinklers rotating

Examples of Newton’s 3rd Law

Newton’s Third Law

• Newton’s Third Law of Motion– When one object exerts a force on a

second object, the second object exerts an equal but opposite force on the first.

Newton’s Third Law

• Action-Reaction Pairs• The rocket exerts a

downward force on the exhaust gases.

• The gases exert an equal but opposite upward force on the rocket.

FG

FR

Newton’s Third Law

For every action there is an equal and opposite reaction.

THANK YOU