Question

The passenger falls forward when a driver of a bus suddenly applies the brakes because of:
1. high speed of the bus
2. inertia of rest
3. inertia of motion
4. high momentum of the bus

Answer 1

Correct Answer - Option 3 : inertia of motion

CONCEPT:

• Newton’s first law of motion: It is also called the law of inertia. Inertia is the ability of a body by virtue of which it opposes a change.
• According to Newton’s first law of motion, an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.
• The inertia of rest: When a body is in rest, it will remain at rest until we apply an external force to move it. This property is called inertia of rest.
• The inertia of motion: When a body is in a uniform motion, it will remain in motion until we apply an external force to stop it. This property is called inertia of motion.

EXPLANATION:

• When the bus stops suddenly, the passenger tends to fall forward. This is because the lower part of the passenger comes to rest with the bus but the upper part tends to continue its motion due to inertia of motion. Thus option 3 is correct.