The equations of motion of a projectile are given by x=36 t metre and 2y=96t-9.8t² metre. The angle of projection is
Options
(a) sin⁻¹ (4/5)
(b) sin⁻¹ (3/5)
(c) sin⁻¹ (4/3)
(d) sin⁻¹ (3/4)
Correct Answer:
sin⁻¹ (4/5)
Explanation:
x = 36t ⇒ dx/dt = 36
.·. vₓ = 36 m/s and 2y = 96t – 9.8t²
⇒ y = 48t – 9.8 t² ⇒ dy/dt = 48 – 9.8t
.·. vᵧ = 48 – 9.8t
At t = 0
⇒ vᵧ = 48
.·. tan θ = vᵧ / vₓ = 48 / 36 = 4 / 3
⇒ sin θ = 4/5 ⇒ θ = sin⁻¹ (4/5)