Question

On what factors does the inertia of motion depend?
(A) Mass
(B) Velocity
(C) Acceleration
(D) Displacement

Answer 1

Hint Inertia is the natural property of an object which forces it to remain in the same state and opposes the change in state. Using this definition, we will judge that what are those factors in which the inertia of motion depends and this definition is enough to guess this.

Step by Step Explanation
In the early of the seventeenth century, Galileo Galilei and his disciples proposed the concept of Inertia which is stated above.
Later, the concept of inertia was modified by Isaac Newton which he stated in his laws of motion. In his Law of Inertia, he stated that “An object will remain in motion if it is in motion or it will be stationary if it is in stationary position until an external force is applied to it.”
For realization, suppose you are in the bus which is moving forward. Suddenly an obstacle came in front of the bus and the driver applied the brakes immediately as soon as he saw the obstacle. What will happen to you and your body. Your body will tend to move in a forward direction after the bus starts slowing down at a greater rate. This property of your body is called inertia.

But this inertia is realized in some reference, and in the above discussed case, we were discussing the inertia in the frame of reference of Earth.
In the above example, just think what would be the tendency of the body that had mass two times to you. His body will be more likely to move forward than yours.
That’s why it’s easy to stop the bicycle compared to a bus , whatever the velocity or acceleration or displacement of them is.

So we can now clearly say that inertia depends on mass among all given options in the question.

Hence the correct option is option (A).

Note We already discussed why and how inertia depends on mass. So, we can say that if there are two bodies with different masses then the inertia in the body with greater mass will act higher than the body with lighter mass, and is independent of mass, velocity and acceleration of both bodies. And the most important thing is that inertia is always realized in some frame of reference.