Posted by Heidi on Wednesday, March 6, 2013 at 9:17pm.
Calculate the ratio of the drag force on a jet flying at 1049 km/h at an altitude of 10.0 km to the drag force on a propdriven transport flying at 560 km/h and at an altitude of 5.00 km. The density of air is 0.380 kg/m3 at 10.0 km and 0.670 kg/m3 at 5.00 km. Assume that the airplanes have the same effective crosssectional area and drag coefficient C.

Physics  drwls, Thursday, March 7, 2013 at 8:05am
The drag force in each case is
C*(1/2)*(air density)*V^2
Ratio (jet/prop) = (0.380/0.670)*(1049/560)^2 = 1.99
Note that I did not have to change dimensions to m/s, since I used the same velocity dimensions for both planes. 
Physics  Heidi, Thursday, March 7, 2013 at 11:55am
Thank you so much... Huge help