question_answer

A stone dropped from the window of a stationary bus takes 4 seconds to reach the ground. In what time the stone will reach the ground when the bus is moving with (a) constant velocity of\[\text{1}0\text{8 km h}{{\text{r}}^{\text{-1}}}\] (b) constant acceleration of\[~\text{2 km }{{\text{h}}^{-\text{2}}}\].

Answer:

                (a) 4 seconds (b) 4 seconds. In both the cases the initial vertical downward velocity is zero and the vertical downward acceleration is acceleration due to gravity g and the stone is to cover the same vertical height in each case.