A ball is projected vertically up from ground.
Boy A standing at the window of first floor of a nearly building observes that the time interval between tha ball crossing him while going up and the ball crossing him while going down is 2s. Another boy B standing on the second floor notices that time interaval between the ball passing him twice, during up motion and down motion is 1 s. Calculate the difference between the vertical positions of boy B and boy A (Assume , acceleration due to gravity , `g=10 m//s^2` )