Finding velocity using Galilean Transformations

AI Thread Summary
The discussion revolves around calculating wind velocity while piloting an airplane due north. The pilot must adjust the plane's nose 22 degrees west of true north due to wind, resulting in a flight time increase from 3.14 hours to 4.32 hours for a 750 km journey. Participants explore using velocity equations and vector representations to determine the wind's magnitude and direction. Initial attempts at calculations lead to incorrect results, but ultimately, one participant successfully resolves the problem. The conversation emphasizes the importance of understanding relative velocities in the context of wind effects on flight.
DODGEVIPER13
Messages
668
Reaction score
0

Homework Statement


You are piloting a small airplane in which you want to reach a destination that is 750 km due north of your starting location. Once you are airborne, you find that (due to a strong but steady wind) to maintain a northerly course you must point the nose of the plane at an angle of 22 west of true north. From previous flights on this route in the absence of wind, you know that it takes you 3.14 h to make the journey. With the wind blowing, you find that it takes 4.32 h. A fellow pilot calls to ask you about the wind velocity (magnitude and direction). What is your report?


Homework Equations


V = L/t
V(prime) = V - U
Theta = invTan(U/V)


The Attempt at a Solution


I have tried multiple ways to solve this prolem and have not even came close I don't believe. What I have done is taken 4.32 - 3.14 = 1.18 sec I figure that is the the amount of time added by the wind. I would assume the wind to be blowing south of east to counteract your angle. So then I said tan(22) = U/V which gives me V= U/tan(22) which gave me an answer of 1573 obviously incorrect. It also occurred to me that maybe what I should have done was this get the velocity of the 4.32h time using V=L/T and also for the 3.14 using the same equation the subtract them and use them in the V = U/tan(22) that got me closer but it was still incorrect.
 
Physics news on Phys.org
DODGEVIPER13 said:

Homework Statement


You are piloting a small airplane in which you want to reach a destination that is 750 km due north of your starting location. Once you are airborne, you find that (due to a strong but steady wind) to maintain a northerly course you must point the nose of the plane at an angle of 22 west of true north. From previous flights on this route in the absence of wind, you know that it takes you 3.14 h to make the journey. With the wind blowing, you find that it takes 4.32 h. A fellow pilot calls to ask you about the wind velocity (magnitude and direction). What is your report?

Homework Equations


V = L/t
V(prime) = V - U
Theta = invTan(U/V)

The Attempt at a Solution


I have tried multiple ways to solve this prolem and have not even came close I don't believe. What I have done is taken 4.32 - 3.14 = 1.18 sec I figure that is the the amount of time added by the wind. I would assume the wind to be blowing south of east to counteract your angle. So then I said tan(22) = U/V which gives me V= U/tan(22) which gave me an answer of 1573 obviously incorrect. It also occurred to me that maybe what I should have done was this get the velocity of the 4.32h time using V=L/T and also for the 3.14 using the same equation the subtract them and use them in the V = U/tan(22) that got me closer but it was still incorrect.
Draw velocity vectors representing the velocity of the airplane relative to the air (A) and the velocity of the airplane relative to the ground (B). What do you do with these vectors to get the velocity vector for the air relative to the ground (C)?

Hint: You know A (750/3.14, N 22 W) and B (750/4.32, N). How do you get vector C from that?

AM
 
Thanks for the answer I figured it out woot!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top