The weight w of an astronaut (in pounds) is related to her height h above the surface of the earth (in miles) by

w= w0(3960/(3960+h))^2

where w0 is the weight of the astronaut on the surface of the earth. If the astronaut weighs 130 pounds on earth and is in a rocket, being propelled upward at a speed of 12 mi/s, find the rate at which her weight is changing (in lb/s) when she is 40 miles above the earth's surface.