Force and Laws of Motion

Introduction

What is Force?

It is a push or pulls on an object that produces an acceleration in the body on which it acts. S.I. unit of force is Newton.
A force can do three things on a body.
•    It can change the speed of the body.
•    It can change the direction of motion of a body.
•    It can change the shape of a body.
Balanced Forces – When equal amounts of forces are applied to an object from different directions such that they cancel out each other, such forces are known as balanced forces.

•    Balanced forces do not change the state of rest or motion of an object.
•    Balanced forces may change the shape and size of an object.
•    If forces nullify one another then their resultant force is zero.
Unbalanced Force – When forces applied to an object are of different magnitude (or not in opposite directions to cancel out each other), such forces are unbalanced forces. 

•    Unbalanced forces can alter the state of rest or motion of an object.
•    Unbalanced forces can cause acceleration in an object.
•    Unbalanced forces can change the shape and size of an object.