let the length of the chord be y
let the horizontal distance of the kite be x ft
given: dx/dt = 5 ?? (looks like a typo in the units)
I will assume you meant:
5 mph = 5280 ft/60 min = 88 ft/min
y^2 = x^2 + 40^2
when y = 50
50^2 = x^2 + 40^2
x = 30
2y dy/dt = 2x dx/dt
dy/dt = 2x dx/dt / 2y
= (x/y)dx/dt
= (30/50)(5) ft/min
= 3 ft/min
( looks quite slow, check my arithmetic)
A kite is 40ft high, with 50ft of cord out. If the kite moves horizontally at 5min per hour directly away from the boy flying it, how fast is the cord being paid out.
1 answer
1 answer