A cart of mass M is tied at one end of a massless rope of length 10 m. The other end of the rope is in the hands of a man of mass M. The entire system is on a smooth horizontal surface. Initially, the man is at x = 0 and the cart at x = 10 m. If the man pulls the cart using the rope, the man and the cart will meet at the point
x = 5 m
Since there is no external force on the man-cart system in the horizontal direction, the centre of mass will not shift. Since their masses are equal, the centre of mass is located at the mid-point between them, i.e. at x = 5 m. Hence, they will meet at x = 5 m and the correct choice is (b).