Explanation:
In horizontal direction there is no acceleration or deceleration for a rock projected at an initial angle of 37° off the ground.
So the horizontal component of velocity always remains the same.
Horizontal component of velocity is the cosine component of velocity.
Initial velocity, u = 21.6 m/s
Angle, θ = 37°
Horizontal component of velocity = u cosθ
Horizontal component of velocity = 21.6 cos37
Horizontal component of velocity = 17.25 m/s
Since the horizontal velocity is unaffected, we have
Horizontal component of the rock’s velocity when it strikes the ground = 17.25 m/s