Question

The blades of a windmill sweep out a circle of area $A$. If the wind flows at a velocity $v$ perpendicular to the circle, then the mass of the air of density $\rho$ passing through it in time $t$ is

• A. $Av\rho t$
• B. $\frac{1}{2}\,Av \rho t$
• C. $Av^2\rho t$
• D. $\frac{1}{2}\,Av^2 \rho t$

Answer 1

Answer: (A)

$Av\rho t$

Answer 2

Answer (a) $Av\rho t$