Question

The mass of object A is 5kg that of object B is 40kg, that of object C is 38kg, and that of object D is 56kg. Which object has the greatest inertia?
a) A
b) B
c) C
d) D

Answer 1

Hint: We know that inertia of an object is the tendency to remain at rest or, if moving, to continue its motion. A body with the highest mass resists changing its position. Using this concept, we can get the required answer.

Complete step by step solution:
Mass is a measure of inertia. The heavier the body, the greater is the force required to change its state and hence greater is its inertia. Thus, in this question, object D is having more mass that is 56kg. Hence object D has more inertia.
In the absence of net external force, the body which is in the state of rest continues to be at rest, and the body which is moving with uniform velocity continues to move with uniform velocity. The body cannot change its state by itself. This property is called inertia. Due to inertia, the body opposes the change of its state.

Additional information:
There are three types of inertia.
Inertia at rest: it is the inability of a body to change its state of rest by itself.
Inertia at motion: it is the inability of a body to change its state of uniform motion by itself. That is a body in uniform motion can neither accelerate nor retard on its own.
Inertia at direction: it is the inability of a body to change its direction of motion by itself. That is a body continues to move along the same straight line unless compelled by some external force to change it.
Newton’s first law gives the concepts of inertia and force. It states that everybody continues to be in its state of rest or uniform motion in a straight line unless an external force acts on it.

From these explanations we can say that, Correct option is (d).

Note:
In simple words we can say, inertia means ‘resistance to change’. This means it opposes the change, that is it does not want to change its state of rest or uniform motion.
Inertia is a measure of mass. Thus SI unit of inertia is kg.
Newton’s first law of motion is also called the law of inertia.