Question

The Garza family uses about 12,000 kWh/year. If they install a wind turbine whose rotor has a diameter of 20 ft, the formula relating annual energy output to annual average wind speed, V, in mph, becomes 12,000=0.01328⋅202⋅V3, which simplifies to 12,000=5.312V3.

Solve 12,000=5.312V3 for V. With a rotor whose diameter is 20 ft, what is the annual average wind speed that the Garzas need to power their home?

Enter your answer into the box. Round to the nearest tenth.

V =
mph

Answer 1

Answer: V = 13.1 mph

Explanation:

12,000 = 5.312V^3

Divide 5.312 from both sides, and on the right side it will cancel out.

12,000/5.312 = V^3

2,259 = V^3

Extract the cube roots of both sides, leaving V^3 to just V.

13.1 = V (I think)