An airplane is flying on a compass heading​ (bearing) of 320 at 335 mph. A wind is blowing with the bearing 300degrees at 50 mph. ​(a) Find the component form of the velocity of the airplane. ​(b) Find the actual ground speed and direction of the plane.

Respuesta :

Answer:

Explanation:

In navigation the angle of the course (on a compass) is counted clockwise from the North (so, the direction to the North is  0°, to the East is 90°, to the South is 180°, and to the West is 270°).

The North on most maps is a vertically up direction.

In coordinate Geometry and Trigonometry, which we will use, angles are measured counterclockwise from the positive direction of the horizontal X-axis (the East on most maps)

Let's make a simple transformation into Trigonometric standard using the direction to the East as an X-axis.:

320° on compass is 90° + ( 360° - 320°) = 130° counterclockwise from the X-axis.

300° on compass is 90° + ( 360° - 300°) = 150° counterclockwise from the X-axis.

This is a problem on addition of two vectors. Each is defined by its amplitude and angle of direction:

airplane (vector  A ) has amplitude  335 mph and angle 130°

wind (vector  W ) has amplitude  50 mph and angle 150°

To add these two vectors, we represent both as sums of X-component and Y-component:

Ax = 345.cos (130°)

Ay = 345.sin (130°)

Wx = 40.cos(150°)

Wy = 40.sin(150°)

Both X-components act along the same direction, both Y-components act along the same direction. So, we can add X-components to get an X-component of the resulting movement and add Y-components to get a Y-component of the resulting movement.

(A+W)x = Ax + Wx = 345.cos(130°) + 40.cos(130°)

(A+W)y = Ay + Wy = 345.sin(150°) + 40.sin(150°)

Knowing two components of the resulting vector of movement, we can easily determine the amplitude |A+W| and direction ∠(A+W)

|A+W| =√(A+W)²x + √(A+W)²y

∠(A+W) = arctan|(A+W)y

                          ----------

                           (A+W)x