two roads cross at right angles one running N/S and the other E/W. 80 ft south of the intersection is an old radio tower. A car traveling at 50 ft/s passes through the intersection heading east. At how many ft/s is the car moving away from the radio tower 3 seconds after it passes through the intersecion?

Question

anonymous · Answer

will award medal

anonymous · Answer

lol please don't leave...

anonymous · Answer

i see people :o

anonymous · Answer

lol no thats not it. its an ap calculus question that i forget how to do. an extremely hard one. the answer is 44.12

anonymous · Answer

use s = sqrt(x^2 + (y-80)^2)  = distance from tower

velocity is ds/dt so differentiate s with respect to t (use chain rule)

the evaluate ds/dt at t=3

anonymous · Answer

yyyeeeesss!!!! thanks you so much I've been waiting for a half hour

anonymous · Answer

Very glad to have been helpful.