Question

Distinguish between:

(1) Force and momentum.

(2) Inertia of motion and inertia of direction

(3) Inertia of motion and inertia of rest.

Answer 1

(1) Force:

The rate of change of momentum of an object is called force.

Its SI unit is newton(N).

Momentum:

It is defined as the product of mass and velocity.

Momentum = massvelocity

Its SI unit is kgm/s.

(2) Inertia of motion:

The tendency of an object to be in uniform motion in a straight line is called inertia of motion. For example: When a moving bus stops suddenly its passengers lean down forward, which is due to the inertia of motion.

Inertia of direction:

The tendency of an object by virtue of which it is not be able to change the direction of its motion is called the inertia of direction.

For example: When an object is in uniform circular motion, it always tries to move tangentially due to the inertia of direction.

(3) Inertia of motion:

The tendency of an object to be in uniform motion in a straight line is called inertia of motion. For example: When a moving bus stops suddenly its passengers lean down forward, which is due to the inertia of motion.

Inertia of rest:

The tendency of an object by virtue of which it is not be able to change its position of rest is called inertia of rest.

For example: When a train starts suddenly, the passengers lean backward.