- #1
picklefeet
- 16
- 0
As most of you know, the drag force equation is Fd=1/2*p*Cd*V^2*Cd*Ac.
At terminal velocity, Fd equals weight. If you find the value of all the variables except Cd and V, you still won't have anything. But the terminal velocity equation is Vt= sqrrt of 2weight/p*Cd*Ac. So if V is terminal velocity, it is reasonable to conclude that V^2 is equivalent to 2W/p*Cd*Ac. So if you replace V^2 with what I've stated above, you'd get W= 1/2p*Cd*2W/p*Cd*Ac.
This equation is true, but only because it cancels out everything but W. You are left with W=W. This is useless for finding Cd. You could also do the opposite. Replace Cd with (1/V^2*2weight)
pAcCd
In this case everything cancels out too. In conclusion, this formula is useless in finding terminal velocity.
At terminal velocity, Fd equals weight. If you find the value of all the variables except Cd and V, you still won't have anything. But the terminal velocity equation is Vt= sqrrt of 2weight/p*Cd*Ac. So if V is terminal velocity, it is reasonable to conclude that V^2 is equivalent to 2W/p*Cd*Ac. So if you replace V^2 with what I've stated above, you'd get W= 1/2p*Cd*2W/p*Cd*Ac.
This equation is true, but only because it cancels out everything but W. You are left with W=W. This is useless for finding Cd. You could also do the opposite. Replace Cd with (1/V^2*2weight)
pAcCd
In this case everything cancels out too. In conclusion, this formula is useless in finding terminal velocity.