A man flies a kite at a height of 15 ft. The wind is carrying the kite horizontally from the man at a rate of 5 ft./s. How fast
must he let out the string when the kite is flying on 32 ft. of string?
1 answer:
Answer:
4.4 ft/s
Step-by-step explanation:
Height = 15ft
Rate= 5 ft/s
Distance from the man to the kite= 32ft
dh/dt = 5 ft/s
h = √32^2 - 15^2
h = √ 1025 - 225
h = √800
h = 28.28ft
D = √15^2 + h^2
dD/dt = 1/2(15^2 + h^2)^-1/2 (2h) dh/dt
= h(225 + h^2)^-1/2 dh/dt
= (h / √225 + h^2)5
= (28.28 / √225 + 28.28^2)5
= (28.28 / √1024.7584)5
= (28.28/32)5
= 0.88*5
= 4.4 ft/s
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