Problem: The pressure (P) of wind on a sail varies jointly as the area (A) of the sail and the square of the velocity (V) of the wind. The pressure on a square foot is 1 pound when the velocity is 16 miles per hour. The velocity of the wind when the pressure on a square yard is 36 pounds is:
Answer Choices:
A. 1032mph
B. 96mph
C. 32mph
D. 132mph
E. 16mph
Solution:
P=kAV2,1=k⋅1⋅162;∴k=1/162
36/9=(1/162)⋅(1)⋅(V2);∴V=32mph