Answer:
0.533 miles/min
Step-by-step explanation:
Calculate how fast the balloon is rising at the moment : dy /dt
location from the lift-off point = 4 miles
angle between the observer's line-of-sight and the horizontal ( ∅ ) = [tex]\frac{\pi }{6}[/tex]
d∅ / dt = 0.1 rad/min
tan ∅ = y / 4
derivate
sec^2 ∅ . d∅ / dt = 1/4 . dy/dt
= sec^2 [tex]\frac{\pi }{6}[/tex] . 0.1 = 1/4 . dy/dt
= ( sec^2 0.5238 * 0.1 ) * 4 = dy/dt
dy/dt = 8 / 15 miles/min
