Question

question 7 of 10
a ball is thrown with a speed of 20 m/s at an angle of 40°. which of the following statements describes the motion of the ball at the top of its trajectory?
a. the vertical component of velocity is zero.
b. the horizontal component of velocity is zero.
c. the horizontal component of velocity is increasing.
d. the vertical acceleration is zero.

Explanation:

In projectile motion, at the top - most point of the trajectory, the vertical velocity component becomes zero as the ball stops moving upwards and is about to start moving downwards. The horizontal component of velocity remains constant (assuming no air - resistance) because there is no horizontal acceleration. The vertical acceleration is always equal to the acceleration due to gravity ($g\approx9.8\ m/s^{2}$) throughout the motion.

Answer:

A. The vertical component of velocity is zero.