Problem 2. Refer to Figure 1 for an illustration of this problem. A pulley is suspended 4 metres above the ground and there is a rope running through the pulley. The length of the rope is 8 metres. A mass is attached to one end of the rope and a person holds the other end of the rope 1 metre above the ground. The person pulls the rope horizontally away from the mass at a speed of 0.5 metres/second. How fast is the mass moving upwards when the person's distance r from the point on the ground below the mass is 6 metres? 7 - 4m h - - 1 m K X Figure 1: Illustration for Problem 2