Question 1

Which of the following is a measure of inertia?

Accepted Answer

Mass is the measure of inertia of an object. The greater the mass, the greater is the inertia and vice-versa.

Question 2

According to the third law of motion, action and reaction:

Accepted Answer

According to Newton's third law of motion, action and reaction act on two different bodies in opposite directions and are equal in magnitude.

Question 3

The SI unit of force is:

Accepted Answer

The SI unit of force is Newton (N), which is equivalent to kg·m/s².

Question 4

Momentum is the product of:

Accepted Answer

Momentum is defined as the product of mass and velocity of an object ($p = m 	imes v$).

Question 5

When a carpet is beaten with a stick, dust particles come out of it. This phenomenon is explained by:

Accepted Answer

This is due to the inertia of rest. The dust particles tend to remain at rest even when the carpet is set into motion.

Force and Laws of Motion — NCERT Class 9 Science Important Questions & Revision Notes