A certain airplane has a speed of 290.0 km/h and is diving at an angle of 30.0° below the horizontal?

Question

when the pilot releases a radar decoy. The horizontal distance between the release point and the point where the decoy strikes the ground is 700 m. (Neglect air resistance.)
a) How high was the plane when the decoy was released?
m
(b) How long was the decoy in the air?
s

Hints:
the answer are:
898.3m for a
10.04s for b
please just show the working

Answer 1

km/hr = 3.6 * m/s
v0 = 290/3.6 m/s
v0(x) = v0*cos(30 deg) = 69.763
v0(y) = v0*sin(30 deg) = 40.278
ans (b). t = s(hor)/v0(x) = 700/69.763 = 10.034
ans (a). s(vert) = v0(y)t + gt^2/2 = 404.144 + 493.836 = 897.980 m
(using g=9.81)