Two boats are headed due north. Boat A is traveling at 25 ft/sec while Boat B is traveling at 15 ft/sec. Boat A is following a course which is 240 ft west of boat B. How fast is the distance between the boats changing when Boat A is 450 ft behind Boat B?
Problems like this call for ol' Pythagoras.
The boats are 240 feet apart. That is constant. Therefore, dx/dt=0
One is travelling at 25 ft/sec and the other at 15 ft/sec. 25-15=10
dy/dt=10 ft/sec.
When x=240 and y=450, then D=510
Differentiate:
Check my figures. I have done this in a hurry.
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