Suppose a snowball remains spherical while it melts, with the radius shrinking at the rate of one inch per hour. How fast is the volume of the snowball decreasing when the radius is two inches? A kite 100 feet above the ground is being blown away from the person holding its string, in a direction parallel to the ground and at the rate of 10 feet per second. At what rate is the person letting the string out when the kite is 175 feet from the person? A board five feet long slides down a wall. At the instant when the bottom end is four feet from the wall, the other end is moving down the wall at the rate of two feet per second. At that moment, how fast is the bottom end line sliding along the ground