Question
A spherical snowball is melting in such a way that it maintains its shape. The snowball is decreasing in volume at a constant rate of 8 cubic centimeters per hour. At what rate, in centimeters per hour, is the radius of the snowball decreasing at the instant when the radius is 10 centimeters? (The volume of a sphere of radius r is \(V=\frac{4}{3}\pi r^{3})\)
A 1/50π
B 3/50π
C 400π
D 3200π
Answer/Explanation
Question
A 10-foot ladder is leaning straight up against a wall when a person begins pulling the base of the ladder away from the wall at the rate of 1 foot per second. Which of the following is true about the distance between the top of the ladder and the ground when the base of the ladder is 9 feet from the wall?
A The distance is increasing at a rate of \(\frac{9}{\sqrt{19}}\) feet per second.
B The distance is decreasing at a rate of \(\frac{9}{\sqrt{19}}\) feet per second.
C The distance is increasing at a rate of \(\frac{\sqrt{19}}{9}\) feet per second.
D The distance is decreasing at a rate of \(\frac{\sqrt{19}}{9}\) feet per second.
Answer/Explanation
Ans:B