Chapter 8, Problem 1A

Distinguish between mass and momentum. Which is inertia and which is inertia in motion?

To determine

To Explain: The difference between mass and momentum.

Explanation of Solution

Introduction:

In Physics, mass is the scalar quantity which defines the inertia of body. Mass can be measured by applying the force on the object and measure its acceleration in the direction of force. According to the Newton’s second law of motion,

  $F=ma\mathrm{...}\left(1\right)$

Momentum is the vector quantity which defined as the product of mass and velocity. Mathematically it can be represented by,

  $p=mv\mathrm{...}\left(2\right)$

Inertia of a body describes the ability to oppose its state of rest or state of motion. According to equation (1), when body in the rest state, due to its mass it acquires the inertia. When body is in the motion, it possesses the momentum. According to Newton’s first law of motion, body continues to be in its state of motion until it is acted upon by the external unbalanced force. The inertia is the property of massive body which opposes the change in its state. The momentum of body is the inertia in motion.

Conclusion:

Thus, mass is the inertia in rest while the momentum is the inertia in motion.