Answer:
The resultant velocity of the helicopter is
.
Explanation:
Physically speaking, the resulting velocity of the helicopter (
), measured in meters per second, is equal to the absolute velocity of the wind (
), measured in meters per second, plus the velocity of the helicopter relative to wind (
), also call velocity at still air, measured in meters per second. That is:
(1)
In addition, vectors in rectangular form are defined by the following expression:
(2)
Where:
- Magnitude, measured in meters per second.
- Direction angle, measured in sexagesimal degrees.
Then, (1) is expanded by applying (2):
(3)
![\vec v_{H} = \left(\|\vec v_{W}\|\cdot \cos \alpha_{W}+\|\vec v_{H/W}\|\cdot \cos \alpha_{H/W}, \|\vec v_{W}\|\cdot \sin \alpha_{W}+\|\vec v_{H/W}\|\cdot \sin \alpha_{H/W} \right)](https://tex.z-dn.net/?f=%5Cvec%20v_%7BH%7D%20%3D%20%5Cleft%28%5C%7C%5Cvec%20v_%7BW%7D%5C%7C%5Ccdot%20%5Ccos%20%5Calpha_%7BW%7D%2B%5C%7C%5Cvec%20v_%7BH%2FW%7D%5C%7C%5Ccdot%20%5Ccos%20%5Calpha_%7BH%2FW%7D%2C%20%5C%7C%5Cvec%20v_%7BW%7D%5C%7C%5Ccdot%20%5Csin%20%5Calpha_%7BW%7D%2B%5C%7C%5Cvec%20v_%7BH%2FW%7D%5C%7C%5Ccdot%20%5Csin%20%5Calpha_%7BH%2FW%7D%20%5Cright%29)
If we know that
,
,
and
, then the resulting velocity of the helicopter is:
![\vec v_{H} = \left(\left(25\,\frac{m}{s} \right)\cdot \cos 240^{\circ}+\left(125\,\frac{m}{s} \right)\cdot \cos 325^{\circ}, \left(25\,\frac{m}{s} \right)\cdot \sin 240^{\circ}+\left(125\,\frac{m}{s} \right)\cdot \sin 325^{\circ}\right)](https://tex.z-dn.net/?f=%5Cvec%20v_%7BH%7D%20%3D%20%5Cleft%28%5Cleft%2825%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5Ccdot%20%5Ccos%20240%5E%7B%5Ccirc%7D%2B%5Cleft%28125%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5Ccdot%20%5Ccos%20325%5E%7B%5Ccirc%7D%2C%20%5Cleft%2825%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5Ccdot%20%5Csin%20240%5E%7B%5Ccirc%7D%2B%5Cleft%28125%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5Ccdot%20%5Csin%20325%5E%7B%5Ccirc%7D%5Cright%29)
![\vec v_{H} = \left(89.894\,\frac{m}{s}, -93.348\,\frac{m}{s}\right)](https://tex.z-dn.net/?f=%5Cvec%20v_%7BH%7D%20%3D%20%5Cleft%2889.894%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%2C%20-93.348%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%5Cright%29)
The resultant velocity of the helicopter is
.