3. Exercises III

 

In moving vehicle like bus, the motion is not uniformuniform, the speed of vehicle variessame and it may apply brake suddenly or takes sudden turn.

 

When some luggage is placed on the roof of a bus which is initially at rest, the acceleration of the bus in the  backward directionforward direction will exert a force in the backward directionforward direction on the luggage.

 

In a similar manner, when a bus which is initially in a state of motion suddenly comes to rest due to the application of brakes, a force in the backward directionforward direction is exerted on the luggage.

 

Depending on the inertiamass of the luggage and the magnitudedirection of the force, the luggage may fall off the bus due to massinertia.

 

So, tying up the luggage will secure its position and prevent it from falling off the bus.