Calculate the ratio of the drag force on a passenger jet flying with a speed of 850 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at three-fifths the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km it is 0.67 kg/m3. Assume that the airplanes have the same effective cross-sectional area and the same drag coefficient C.

Question

Calculate the ratio of the drag force on a passenger jet flying with a speed of 850 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at three-fifths the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km it is 0.67 kg/m3. Assume that the airplanes have the same effective cross-sectional area and the same drag coefficient C. 
(drag on jet / drag on transport) =

bobpursley · Answer

Surely you have an equation for drag force as a function of density, C, and speed.

Sam · Answer

I have D=.5CpAv^2, do i just ignore C and A?? not quite sure what to do...

Sam · Answer

Okay i figured it out. thanks for your assistance I wasn't looking in the right place