A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s².What is the horizontal component of its velocity after 4.0 s? A)150 m/s B)35 m/s C)130 m/s D)75 m/s E)38 m/s

Question

Quizplus · Accepted Answer

First, we can find the initial horizontal and vertical components of the velocity:

Vx = 150 cos(30°) = 129.9 m/s
Vy = 150 sin(30°) = 75 m/s

Since there is no air resistance, the horizontal component of the velocity remains constant throughout the motion. Therefore, after 4.0 s, the horizontal velocity is still 129.9 m/s.

Alternatively, we can use the formula for horizontal displacement:

x = Vx * t = 129.9 m/s * 4.0 s = 519.6 m

Therefore, the horizontal component of the velocity after 4.0 s is 129.9 m/s or approximately 130 m/s (Choice C).

A Projectile Is Fired from Ground Level with a Speed