A man with mass m is standing at the far end of a flat platform of mass M and length L as shown in Fig.(1). The initial distance of the man from the origin is D, and at t = 0, he starts to move towards the origin. What will be the distance between the man and the origin after he has moved a distance h with respect to the platform? Assume the platform has a uniform mass distribution and treat the man as a point particle. The surface between the platform and the ground is frictionless.

Figure 1