- #1
Addez123
- 199
- 21
- Homework Statement
- A plane flies at a height of 15km with velocity of 1200km/h.
Another plane flies at half that speed and altitude.
Air density at 10km is .38
Air density at 5km is .67
Assume they have same cross section area A and drag coefficient C.
Calculate the ratio of the dragforce of the two planes.
- Relevant Equations
- D = 1/2 * CpA*v^2
Just calculating D1 (15km altitude plane) and D2 (7.5km altitude plane) turns out to;
D1/D2 = 4*p1/p2
p being the air density at each height.
How am I suppose to calculate p? We have had no such formulas, not to mention it depends on temprature etc.
Doing a linear estimation will yield wrong answer.
Correct answer is 3.3
D1/D2 = 4*p1/p2
p being the air density at each height.
How am I suppose to calculate p? We have had no such formulas, not to mention it depends on temprature etc.
Doing a linear estimation will yield wrong answer.
Correct answer is 3.3