SOLUTION: The force of the wind on a sail varies jointly as the area of the sail and the square of the wind velocity. On a sail of area 50 sq. yd, the force of a 15 mph wind is 45 pounds. Fi

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Question 1186506: The force of the wind on a sail varies jointly as the area of the sail and the square of the wind velocity. On a sail of area 50 sq. yd, the force of a 15 mph wind is 45 pounds. Find the force on the sail if the wind increases by 30 mph.
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39625) About Me  (Show Source):
You can put this solution on YOUR website!
F, the force
a, the sail area
v, the wind velocity
k, variation constant

First sentence is F=kav%5E2

The second sentence lets you get the value for k.

k=45%2F%2850%2A15%5E2%29
k=0.004

The formula becomes F=0.004%2Aa%2Av%5E2
.
.

Answer by ikleyn(52855) About Me  (Show Source):
You can put this solution on YOUR website!
.

The speed of the wind increased from 15 mph to 15 + 30 = 45 mph.

The area of the sail did not change.


With the speed of the wind increased thrice, the new force is 3^2 = 9 times as large as 45 pounds, i.e. 


     9 * 15 = 135  pounds.    ANSWER

Solved and answered.