Instruments in an airplane which is in level flight indicate that the velocity relative to the air (airspeed) is 180.00 km/h and the direction of the relative velocity vector (heading) is 70° east of north. Instruments on the ground indicate that the velocity of the airplane (ground speed) is 150.00 km/h and the direction of flight (course) is 60° east of north. Determine the wind speed and direction. (Round the final answer to two decimal places.)

Respuesta :

Answer:

Explanation:

From the given information:

The coordinate axis is situated in the east and north direction.

So, the north will be the  y-axis and the east will be the x-axis

Similarly, the velocity of the plane in regard to the air in the coordinate system will be [tex]v_{P/A} = v( cos \theta \ i + sin \theta \ j)[/tex]

where:

[tex]v_{P/A}[/tex] = velocity of the plane in regard to the air

v = velocity

θ =  angle of inclination of the plane with respect to the horizontal

replacing v = 180 km/ and θ = 20° in above equation, then:

The velocity of the airplane in the coordinate system as:

[tex]v_{P} = v_o( cos \phi \ i + sin \phi \ j)[/tex]

where;

[tex]v_p[/tex] = velocity of the airplane

[tex]v_o[/tex] = velocity

∅ = angle of inclination with regard to the base axis;

Then; replacing  [tex]v_o[/tex]  = 150 km/h and ∅ = 30°

Therefore, the velocity of the plane in the system is :

[tex]v_p = v_A + v_{P/A}[/tex]

[tex]v_A= v_P -v_{P/A}[/tex]   --- (1)

[tex]v_A=[/tex] ( 150 cos 30° - 180 cos 20°)i + ( 150 sin 30° - 180sin 20°)j

[tex]v_A=[/tex] (-39.24 km/h)i + (13.44 km/h) j

The magnitude is:

[tex]v_A= (-39.24 km/h)i + (13.44 km/h) j[/tex]

[tex]|v_A|^2 = \sqrt{ (-39.24 km/h)^2+ (13.44 km/h)^2}[/tex]

[tex]v_A[/tex] = 41.48 km/h

The airplane is moving at an angle of the inverse tangent to the abscissa and ordinate.

The angle of motion is:

tan θ = 39.24/13.44

tan θ = 2.9

θ  = [tex]tan ^{-1} (2.9)[/tex]

θ  =  70.97°

The angle of motion is  70.97° from west of north with a velocity of 41.48 km/h.