A small plane is flying northeast at a speed of 200 mph. A wind blows due west at 28 mph. Find the resultant speed and direction of the plane.

Respuesta :

Answer:

The resultant speed = 181.3 mph

The final direction = 38.7° northeast.

Step-by-step explanation:

We need to find the component in the x-direction and in the y-direction of the speed:

For the plane:

[tex] v_{p_{x}} = 200cos(45) = 141.42 [/tex]

[tex] v_{p_{y}} = 200sin(45) = 141.42 [/tex]

For the wind we have:

[tex] v_{w_{x}} = -28 [/tex]

[tex] v_{w_{y}} = 0 [/tex]

Now, the total speed in the x-direction and  in the y-direction is:

[tex] V_{x} = v_{p_{x}} + v_{w_{x}} = 141.42 - 28 = 113.42 [/tex]

[tex] V_{y} = v_{p_{y}} + v_{w_{y}} = 141.42 [/tex]

Hence, the resultant speed is:

[tex] V = \sqrt{V_{x}^{2} + V_{y}^{2}} = \sqrt{(113.42)^{2} + (141.42)^{2}} = 181.3 mph [/tex]

Finally, the direction of the plane is:

[tex] tan(\theta) = \frac{V_{y}}{V_{x}} = \frac{141.42}{113.42} = 1.25 [/tex]

[tex] \theta = 51.3 ^{\circ} [/tex]

[tex] \theta = 90 - 51.3 = 38.7 ^{\circ} [/tex]

The plane is moving at 38.7° northeast.

I hope it helps you!