A man standing inside a room of length L rolls a ball along the floor at time `t = 0`. The ball travels at constant speed v relative to the floor, hits the front wall (B) and rebounds back with same speed v. The man catches the ball back at the wall A at time `t_(0)`. The ball travelled along a straight line relative to the man inside the room. Another observer standing outside the room found that the entire room was travelling horizontally at constant velocity v in a direction parallel to the two walls A and B.

(a) Find the average speed of the ball in the time interval `t = 0` to `t = t_(0)` as observed by the observer outside the room.
(b) If the room has acceleration in the direction of its velocity draw a sketch of the path of the ball as observed by the observer standing outside. Assume that velocity of room was v at the instant the ball was released.

Answer

(a) `sqrt(2)v` (b) path is as shown
`(##IJA_PHY_V01_C02_E01_132_A01##)`