Explain why a person travelling in a bus falls forward when bus stops suddenly

Cause of Inertia of Motion

Explanation:

It can be explained as follows...when the moving bus suddenly stops, the lower part of the body of the passenger contact with the bus suddenly comes to rest while the upper part of the body tends to retain its state of motion due to inertia. As a result, the passenger is thrown forward.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.