Introduction

→ Force: It is the force that enables us to do any work. To do anything, either we pull or push the object. Therefore, pull or push is called force.

Example, to open a door, either we push or pull it. A drawer is pulled to open and pushed to close.  Effects of Force

→ Force can make a stationary body in object.

For example: a football can be set to move by kicking it i.e. by applying a force. → Force can stop a moving body.

For example, by applying brakes, a running cycle or a running vehicle can be stopped. → Force can change the direction of a moving object.

For example: by applying force i.e. by moving handle, the direction of a running bicycle can be changed. Similarly by moving steering, the direction of a running vehicle is changed. → Force can change the speed of a moving body. By accelerating, the speed of a running vehicle can be increased or by applying brakes the speed of a running vehicle can be decreased. → Force can change the shape and size of an object.

For example: by hammering, a block of metal can be turned into a thin sheet. By hammering, a stone can be broken into pieces. 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. 