0Newtons laws of motion:
- First law: Law of inertia: Every body continues to be in its state of rest or of uniform motion in a straight line unless compelled to change that state by an external unbalanced force.
- Second law: The rate of change of momentum is directly proportional to the external unbalanced force and takes place in the direction of force.
- Third law: To every action, there is an equal and opposite reaction.
Force and Inertia:
Force: Force is that which changes or tends to change the state of rest or of uniform motion of a body in a straight line.
For Eg:
(i) A body remaining at rest cannot be moved without the help of an external force.
(ii) A freely rolling body will come to rest due to frictional force. So, in order to change the state of a body, we need a force. So a body by itself cannot change its state of rest or of uniform motion in a straight line. This property of all bodies is called inertia.
Inertia: Inertia is the inability of a material body to change by itself its state of rest or of uniform motion in a straight line.
