A light is mounted at the top of a pole, 12 feet above the ground. A man 6.5 feet tall walks away from the pole at a rate of 4 feet per second. (a) How fast is the tip of his shadow moving when he is 10 feet from the base of the pole? Enter the exact answer. The tip of his shadow is moving away from the pole at a rate of Number feet per second. (b) How fast is the length of his shadow changing when he is 10 feet from the base of the pole? Enter the exact answer. The length of his shadow is growing at a rate of Number feet per second