Question

a passenger in a moving bus with no window notices a ball at rest in the aisle suddenly starts to move backwards.think of two different possible scenario and desive a way to decide which is corret.​

Answer 1

This would happen if the bus is suddenly on an inclined road or if the bus is accelerating. For example, we can take a pendulum of known length. In the inclined bus, the only force acting on the pendulum would be gravity and its' frequency would remain unchanged, while in the accelerating bus we would have the inertial force acting on the pendulum and its' frequency would increase.