Question

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

Answer 1

Inertia:

1. When some luggage is placed on the roof of a bus that is originally at rest, the bus's forward acceleration will impose a force on the luggage (in the backward direction).
2. In a similar manner, when a bus comes to a stop rapidly due to the use of brakes, a force (in the forward direction) is imposed on the luggage.
3. Due to inertia, the luggage may fall off the bus depending on its mass and the magnitude of the force. The luggage will be secured and will not fall off the bus if it is tied up.