Question

which of the following graphs represents the horizontal velocity component (vx) versus time (t) for a projectile thrown horizontally off a cliff? (ignore air resistance.)

Explanation:

Step1: Recall projectile - motion principles

In projectile motion, when air - resistance is ignored, the horizontal component of velocity ($v_x$) remains constant because there is no horizontal acceleration ($a_x = 0$). The vertical component of velocity ($v_y$) changes due to the acceleration of gravity ($a_y=-g$). The horizontal velocity does not depend on time in the absence of air - resistance.

Step2: Analyze the graphs

A graph of horizontal velocity ($v_x$) versus time ($t$) should be a horizontal line, indicating a constant value.

Answer:

D