A ball of mass 0.01 kg is suspended from a fixed point O by means of a light and inextensible string of length 10m. The ball is first taken aside such that string becomes horizontal and then released from reast. At the lowermost point of its path, it hits a stationary small block of mass 1.205kg lying on a rough horizontal surface. After striking the block, the ball rebounds and comes to rest when the string makes an angle of `30^@)` with the horizontal . Due to the impact the block moves through a distance of 0.5m on the horizontal surface. Find the coefficient of friction between the block and the surface.

Answer

0.004