Question

It is advised to tie any luggage kept on the roof of a bus with a rope because of:
A. Newton’s first law
B. Newton’s second law
C. Newton’s third law
D. None of these

Answer 1

Every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. To answer the question correctly, we will have to use the various concepts of inertia. There are different types of inertia which are inertia of rest, inertia of motion and inertia of direction.

Complete answer:
When the luggage is kept on the roof of a bus and the bus is in motion then the luggage is also in motion but when the bus driver suddenly applies brakes to bring the bus to complete halt, then the luggage tend to remain in the state of motion because of Newton’s first law or law of inertia.

Due to Newton's first law, when the bus will stop but the luggage will remain in the motion and it will ultimately fall. Similarly, when a bus suddenly starts, the luggage on the roof of the bus tends to remain in the state of rest and fall down from the roof of the bus. It is happening because the state of difference arises between the bus and the luggage. To avoid these types of incidents, it is advised to tie luggage with a rope on the surface of the bus.

Hence, option A is correct.

Note: We should have a clear understanding of inertia if certain types of questions are posed. Owing to the inertia of rest, the baggage appears to sit at rest as the bus passes. That is why when the bus begins, the baggage drops backwards. As the bus slows, owing to inertia in motion, the baggage appears to stay in motion and rolls forward.