Question

Which one of the following best describes the vertical part of a projectile's motion?

• A. It moves at a constant vertical velocity
• B. It moves at a continually changing vertical velocity
• C. It always has zero vertical velocity
• D. The answer to this question depends on whether it is fired horizontally or at an angle

Answer 1

The correct option is B It moves at a continually changing vertical velocity

In projectile motion, there is no acceleration in the horizontal direction therefore horizontal velocity remains constant through the whole journey .

Whereas in vertical direction object is under the effect of constant acceleration that is gravitational acceleration $g$ , therefore object moves with a continuously changing vertical velocity .