A boy standing on a long railroad car throws a ball straight upwards. The car is moving on the horizontal road with an acceleration of 1 ms-2 and the projection velocity in the vertical direction is 9.8 ms-1. How far behind the boy will the ball fall on the car? (in meters)

Let the velocity of car be u when the ball is thrown.Initial velocity of car = Horizontal velocity of ball.Distance travelled by ball B,Sb=ut (in horizontal direction) Car has travelled extra distance=Sc-Sb=ut+12at2-ut=12at2Ball can be considered a projectile having θ = 900t=2usin⁡θg=2×9.89.8=2sSc−Sb=12at2=12(1)22=2mHence, the ball will drop 2 m behind the boy.