Question

Define inertia and momentum.

Answer 1

Inertia - Inertia is the property of a body by which it resists a change in its state of motion. It is directly proportional to the mass of the body. For example, when we switch off a fan, it does not come to the state of rest immediately.
Momentum - Momentum can be defined as the product of the mass of a body and its velocity.
Momentum = Mass $\times$ Velocity