Newton’s Newton’s Laws of Laws of MotionMotion

I.I. Law of Inertia Law of Inertia

II.II. F=ma F=ma

III.III. Action-Reaction Action-Reaction

Newton’s Laws of MotionNewton’s Laws of Motion

11stst Law Law – Inertia– Inertia 22ndnd Law Law – – F=maF=ma 33rdrd Law Law – – Action-ReactionAction-Reaction

33rdrd Law Law

For every action, there is an For every action, there is an equal and opposite reaction.equal and opposite reaction.

33rdrd Law Law

When objects A and B When objects A and B interact with each other, interact with each other, they exert forces upon they exert forces upon each other. When you each other. When you sit in your chair, your sit in your chair, your body exerts a downward body 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

There are two forces There are two forces resulting from this resulting from this interaction - a force on interaction - a force on the chair and a force on the chair and a force on your body. These two your body. These two forces are called forces are called actionaction and and reactionreaction forces. forces.

Newton’s 3rd Law in NatureNewton’s 3rd Law in Nature ActionAction

Fish pushed the water back Fish pushed the water back with its finswith its fins

Reaction Reaction Water pushed the fish forwardWater pushed the fish forward

The size of the force on the The size of the force on the water equals the size of the water equals the size of the force on the fish force on the fish

The direction of the force on The direction of the force on the water (backwards) is the water (backwards) is opposite the direction of the opposite the direction of the force on the fish (forwards).force on the fish (forwards).

33rdrd Law Law

ActionAction Bird pushed the air Bird pushed the air

down as it flaps its down as it flaps its wings.wings.

Reaction Reaction Air pushes the bird Air pushes the bird

up causing lift.up causing lift.

33rdrd Law Law

ActionAction Bat hits ball.Bat hits ball.

Reaction Reaction Ball hits bat.Ball hits bat.

33rdrd Law - Law - Gun Recoil

ActionAction Gun fires bullet Gun fires bullet

forward out of the forward out of the barrel.barrel.

Reaction Reaction Bullet pushes the gun Bullet pushes the gun

backwards.backwards.