A projectile is launched at 37 degrees to the horizontal with a speed of 200 m/s from position A. How many seconds elapse after launch of the projectile before it returns to its original elevation at C?

a. 12 s

b. 16 s

c. 41 s

d. 33 s

e. 24 s

e. 24 s

Explanation:

Time of flight of a projectile: This is the time taken for a projectile to return to the same plane at which it was projected. The time of flight of a projectile is expressed as,

T = 2Usinθ/g ... Equation 1

Where T = Time of flight, U = initial velocity, θ = angle of projection to the horizontal, g = acceleration due to gravity.

Given: U = 200 m/s, θ = 37°, g = 9.81 m/s²

Substitute into equation 1,

T = 2 (200) (sin37°) / 9.81

T = 400 (0.60) / 9.81

T = 24.46

T ≈ 24 s.

The right option is e. 24 s