Answer:
[tex]\theta = 49.56 degree[/tex]
Explanation:
Relative horizontal velocity of plane with respect to the car is given as
[tex]v_r = v_p - v_c[/tex]
so we have
[tex]v_p = 215 km/h[/tex]
[tex]v_c = 155 km/h[/tex]
now we have
[tex]v_r = 215 - 155 [/tex]
[tex]v_r = 60 km/h[/tex]
[tex]v_r = 16.67 m/s[/tex]
Now time taken by the object to drop the vertical height is given as
[tex]y = \frac{1}{2}gt^2[/tex]
[tex]78 = \frac{1}{2}(9.81)t^2[/tex]
[tex]t = 3.98 s[/tex]
so the distance of the car must be
[tex]d = v_r\times t[/tex]
[tex]d = 16.67 \times 3.98[/tex]
[tex]d = 66.47 m[/tex]
Angle of the car with horizontal is given as
[tex]tan\theta = \frac{y}{x}[/tex]
[tex]tan\theta = \frac{78}{66.47}[/tex]
[tex]\theta = tan^{-1}(1.17)[/tex]
[tex]\theta = 49.56 degree[/tex]