B.2.1.1 (3) Newton's laws of motion

Name of the law (Newton's law)

Definition

Apply to a sporting example

1. Law of inertia

Bodies or objects stay where they are or keep moving unless acted on by an unbalanced force

An example of this is when an ice hockey puck is stationary on the ice. The force of the weight of the puck is balanced by the upward force from the ice, so it is at rest. However, when a player hits the puck, an unbalanced external force is applied to it so it accelerates in the direction of the hit. It then travels across ice, being slowed slightly by friction, until another force changes its motion again

2. Law of acceleration

Force is equal to mass multiplied by acceleration

The different forces required to accelerate a table tennis ball and a soccer ball. To give the soccer ball the same acceleration as a table tennis ball, the player must apply a larger force because the soccer ball has a greater mass than the table tennis ball

3. Law of action and reaction

For every action there is an equal and opposite reaction

Newton’s third law is important when a sprinter starts a race from the blocks. They must push backwards and downwards with large forces onto the blocks. The blocks will then push back onto the sprinter with the same force, but in the opposite direction.