Question

a man in a boat rowing from light house whose height is 200 meter.he takes 2minutes to change the angle of elevation top of light house from 60⁰ and 45⁰ find speed of boat​

Answer 1

Answer:

The speed of the boat is approximately 0.704 m/s

Step-by-step explanation:

The time it takes the man in the boat to change the angle of elevation from 60° to 45°, t = 2 minutes = 120 seconds

The height of the light house = 200 m

Given that the angle of elevation is reducing, the direction of the man is away from the lighthouse

The initial distance of the man in the boat from the lighthouse = 200 m/(tan(60°)) = (200/√3) m

The final distance of the man in the boat from the lighthouse = 200 m/(tan(45°)) = 200 m

The distance traveled in 2 minutes, d = 200 m - (200/√3) m ≈ 84.53 m

The speed of the boat, v = d/t

∴ v = 84.53 m/(2 min × 60 s/min) ≈ 0.704 m/s

The speed of the boat, v ≈ 0.704 m/s.