2. Linear Motion and Force Flashcards
Linear motion
When a body moves in a straight or curved line, with all parts moving in the same direction and at the same speed.
Example of linear motion
A performer in the skeleton bobsleigh will travel with linear motion sliding down the straight parts of the track and with linear motion in a curved line when sliding around the bends.
What is action force?
A force applied by a performer on another body
Example of an action force
The backward and downward action force exerted by a sprinter on the blocks at the start of a race
What is a reaction force?
An equal and opposite force to the action force exerted by a second body on the first
What is an internal force?
Generated by the contraction of skeletal muscle
Example of an internal force
100m sprinter contracts leg muscles to generate force required to drive away from blocks
What is an external force?
Comes from outside the body and acts upon it.
The force of weight, reaction, friction and air resistance.
What is net force?
The sum of all forces acting on a body, also called the resultant force.
It’s the overall force acting on a body when all individual forces have been considered.
What does it mean if net force = 0?
There is no change in motion as the forces are balanced.
Example of net force
Rugby scrum, both packs push forwards with equal force so the net force = 0
What happens if a net force is present?
There is a change in motion as the forces are unbalanced
What happens if a net force is positive?
A body will accelerate
Example of a positive net force
When a net baller makes a chest pass, the forward force applied is greater than the air resistance.
