A conveyor belt is moving at a constant horizontal velocity. A block lands on it with a horizontal velocity 5 m/s with respect to ground in direction...

A conveyor belt is moving at a constant horizontal velocity. A block lands on it with a horizontal velocity 5 m/s with respect to ground in direction opposite to the motion of the belt. After 4 seconds of this incident the block starts moving with the belt. Friction coefficient between the block and the belt is 0.2. Find the velocity of the belt.