Q 3.25 On a long horizontally moving belt (Fig. ), a child runs to and fro with a speed 9 km h-1 (with respect to the belt) between his father and mother located 50 m apart on the moving belt. The belt moves with a speed of 4 km h-1. For an observer on a stationary platform outside, what is the
(c) time taken by the child in (a) and (b)?
Which of the answers alter if motion is viewed by one of the parents?