Question

What do you mean by inertia? Illustrate with two examples.

Answer 1

Hint: In order to answer this question, we need to understand Newton's $1st$ law of motion in which inertia is described. First, we need to clear the concept regarding this law then we can write the answer with ease.

Complete step-by-step solution:
Newton’s $1st$ law of motion states that: If a body is at rest or moving at a constant speed, it continues to be in the same state unless a force acted upon. This law is also called the Law of Inertia.
The property of a body by virtue of which it opposes any change in state of an object is known as Inertia. Inertia is a passive property and does not enable a body to do anything except oppose such active agents as forces and torques.
There are two measures of inertia as follows:
Mass: It opposes the action of force
Moment of inertia about a specific axis: It resists the action of torque in rotational motion.
There are three types of Inertia:
Inertia of rest: A body remains there where it is placed or at rest until a force is exerted on it.
Inertia of motion: A body will continue in motion unless a resistive force is applied on it.
Inertia of direction: A body will remain in the same direction until a force changes its direction.
Examples of Inertia:
Passengers experience a jerk in forward direction in the bus when it stops. In this example, passengers are in inertia of motion.
Leaves fall when we shake the branch of the tree. In this example, leaves are in inertia of rest.

Note: There are three laws of motion (Newton’s law of motion) as follows:
$1st$law of motion: If a body is at rest or moving at a constant speed, it continues to be in the same state unless a force acted upon. This law is also called the Law of Inertia.
$2nd$law of motion: The acceleration of a body produced by a force is directly proportional to the magnitude of net force, in the same direction as the force and inversely proportional to mass of the body.
Mathematical representation,$a = \dfrac{{{F_{net}}}}{m}$
$3rd$law of motion: For every action, there is an equal and opposite force.
i.e.,${F_{ma}} = {F_{am}}$