3. Types of inertia

 

 

The inherent property of a body to resist any changeallow any changemodify any changenone of the above in its state of rest or the state of uniform motion, unless it is influenced upon by an external balanced forceexternal unbalanced forceinternal forcenone of the above, is known as ‘inertia’.

 

There are three types of inertia:

The resistance of a body to change its state of restdirection of motionstatic directionstate of motion is called inertia of rest.

The resistance of a body to change its state of motiondirection of motionstate of reststatic direction is called inertia of motion.

The resistance of a body to change its direction of motionstate of motionstate of rest is called inertia of direction.

Examples:

 

Inertia of motion: A passenger leans outward when a bus turns sharply.When a moving bus stops suddenly, passengers tend to fall forward.Water spills from a glass when the glass is suddenly turned or jerked. A book lying on a table does not move unless pushed.

Inertia of rest:Passengers lurch forward when a car stops suddenly.Water spills from a glass when the glass is suddenly turned or jerked. A ball moving in a straight line continues straight when the ground curves under it.A parked car does not start moving unless someone applies a force.

Inertia of direction: 

A stone on the ground stays stationary until thrown or kicked.Passengers lurch forward when a car stops suddenly.Passengers lurch forward when a car stops suddenly. A passenger leans outward when a bus turns sharply..