Force and motion are related and force is the cause of motion, as force affects the state of motion of an object.
An object moves when some force acts on it or has acted on it which produced this motion.
Motion can either be described as
Change in speed, or
Change in direction.
From the studies of Sir Isaac Newton, three conclusions can be made on force and motion:
Force can cause a body to accelerate
Force can cause a body to change directions
Force can cause a body to decelerate
FORCE CAN CAUSE A BODY TO ACCELERATE
A body at rest starts moving when a force is applied to it, provided that there is no greater force opposing it.
For example, when a bowler throws a ball, it starts to move forward from its initial position of rest in his hands.
When something begins to move from a state of rest, it accelerates. Acceleration can be described as the positive change in velocity over a period of time.
If force is applied in the same direction of movement of a moving object, it accelerates. For example, rotating the pedal of a bicycle will make it go faster.
FORCE CAN CAUSE A BODY TO CHANGE DIRECTIONS
An object changes motion when force is applied on it in an angle different to its direction of motion. Almost every ball game uses this principle.
The speed can be maintained if the force is applied in a perpendicular angle but the velocity will change
FORCE CAN CAUSE A BODY TO DECELERATE
If force is applied on the opposite direction of a moving object, it will decelerate or slow down and eventually stop altogether if the force is continued to be applied.
For example, when a goalkeeper stops a ball, he causes it to decelerate and stop.
