question_answer

A boy of mass 20 kg is standing on a 80 kg free to move long cart. There is negligible friction between cart and ground. Initially, the boy is standing 25 m from a wall. If he walks 10 m on the cart toward the wall, then the final distance of the boy from the wall will be:                                                                    [JEE ONLINE 23-04-2013]

A)         15 m  

B)        12.5 m

C)   15.5 m           

D)        17 m