Question

The inertia of an object tends to cause the object:
A. To increase its speed.
B. To decrease its speed.
C. To resist any change in its state of the motion
D. To decelerate due to friction.

Answer 1

To answer this question to know how of the inertia which is also called Newton’s first law of motion by this definition we bend to know what is inertia.

Complete answer:
Law of inertia:
An object will continue to be in the state of the rest or in a state of the motion unless an external force acts on it. This law is also known as Newton's first law of the motion.

Now let’s come to our question and find the right option using the definition,
Option (A) to increase speed.
Speed cannot be increased without an external force hence this option is incorrect.

Consider Option (B) to decrease speed.
To change the speed of the body you need external force. By the law of inertia it states that if the body is in motion it will continue its motion hence speed cannot be changed.
Therefore, the option (B) is also incorrect.

Consider Option (C) to resist any change in its state of the motion.
This option is correct and approved by the law of inertia which states that if a body is in motion it continues its motion until external force is applied on it.
Therefore option (C) is correct.

Option (D) to decelerate due to friction.
Friction is also an external force which tends to decrease motion of the body hence it will violate the law of the inertia.
Hence, the option (D) is incorrect.

Therefore, the correct answer is option (C).

Note:
Do not mistake inertia as a moment of inertia because it is a quantity expressed by the body resisting angular acceleration which is the sum of the product of the mass of every particle with it’s square distance from the axis of the rotation.