Work, Power and EnergyHard
Question
A wind - power generator converts wind energy into electric energy. Assume that the generator converts a fix friction of wind energy intercepted by its blades into electrical energy. For wind speedv, the electrical power output will be proportional to
Options
A.v
B.v2
C.v3
D.v4
Solution
Power = 
= Fv
F = v
= ρv
= ρv(Av) = ρAv2
∴ Power P = ρAv3 or P ∝ v3
= FvF = v
= ρv
= ρv(Av) = ρAv2 ∴ Power P = ρAv3 or P ∝ v3
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