One end of a 10 m long ladder is on the ground and the ladder is supported partway along its length by resting on a top of 3 m high fence. If the bottom of the ladder is 4 m from the base of the fence and is been dragged along the ground away from the fence at a rate of 1=5 m/s, how fast is the free top end of the ladder moving (a) vertically downward and (b) horizontally to the right?