If the wind blows for one year at a steady 10 m/sec, how much would be the energy we could get in this year per square meter of cross section through the use of a windmill? Express the answer in kWh. (use air density of 1kg/m3)
2007-11-28 04:34:33 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
This would be equal to the total kinetic energy of all the air passing through the cross-section. If the speed of the wind is v and it passes through a cross-section A, then the volume of air passing through the cross-section in time t would be V = Avt. If the air has density p, its mass would be m = Vp = Avtp. And since kinetic energy is KE = 0.5*mv^2, the total kinetic energy of the air would be KE = 0.5*Atpv^3. Since we're looking for energy per cross-sectional area, we divide by A to get a final answer of 0.5*tpv^3. You've been given p, v, and t. However, time t was given as one year, so you need to convert it into seconds.
2007-11-30 01:05:03 · answer #1 · answered by DavidK93 7 · 0⤊ 0⤋