Question

A balloon of radius r subtends an angle  at the eye of an observer and the elevation of the centre of the balloon from the eye is , then the height h of the centre of the balloon is given by

Answer 1

Let C be the position of John. Let A be the position at which balloon leaves the earth and B be the position of the balloon after 2 minutes.

Given that CA = 150 m, BCA = 60°

tan60°=BACA√3=BA150BA=150√3tan⁡60°=BACA3=BA150BA=1503

i.e, the distance travelled by the balloon =150√3=1503 meters
time taken = 2 min = 2 × 60 = 120 seconds

Speed =DistanceTime=DistanceTime
=150√3120=1.25√3=1.25×1.73=2.16 meter/second