newtons_laws_of_motion2008

Newton’s Laws of Motion : 

Newton’s Laws of Motion March 30, 2010

Objectives : 

Objectives Explain the three laws of motion

1st Law of Motion (Law of Inertia) : 

1st Law of Motion (Law of Inertia) An object at rest will stay at rest, and an object in motion will stay in motion traveling in a straight line, unless acted upon by an unbalanced force.

Slide 4: 

Because of inertia, objects resist changes in their motion. When the car going 80 km/h is stopped by the brick wall, your body keeps moving at 80 km/h. Wear a seatbelt!

Slide 5: 

Why then, do we observe every day objects in motion slowing down and becoming motionless seemingly without an outside force?

Slide 6: 

There are four main types of friction: Sliding friction: ice skating Rolling friction: bowling Fluid friction: air or water resistance Static friction: initial friction when moving an object Friction!

2nd Law : 

2nd Law F = ma

2nd Law : 

2nd Law The net force of an object is equal to the product of its mass and acceleration.

Newton’s 2nd Law proves that different masses accelerate to the earth at the same rate, but with different forces. : 

Newton’s 2nd Law proves that different masses accelerate to the earth at the same rate, but with different forces. We know that objects with different masses accelerate to the ground at the same rate. However, because of the 2nd Law we know that they don’t hit the ground with the same force. F = ma 98 N = 10 kg x 9.8 m/s/s F = ma 9.8 N = 1 kg x 9.8 m/s/s

3rd Law : 

3rd Law For every action, there is an equal and opposite reaction. Forces always act in pairs

Newton’s 3rd Law in Nature : 

Newton’s 3rd Law in Nature A fish uses its fins to push water backwards. The water reacts by pushing the fish forwards, propelling the fish through the water.

3rd Law : 

3rd Law As the birds push down on the air with their wings, the air pushes their wings up and gives them lift.

Other examples of Newton’s Third Law : 

Other examples of Newton’s Third Law The baseball forces the bat to the left (an action); the bat forces the ball to the right (the reaction).

3rd Law : 

3rd Law Various fuels are burned in the engine, producing hot gases. As the gases move downward, the rocket moves in the opposite direction.