Projectile motion is not constant motion. Here's why:

* Constant velocity: Constant motion implies constant velocity, meaning both speed and direction are unchanging. Projectile motion, however, involves a constant acceleration due to gravity, which means the vertical velocity is always changing.

* Parabolic trajectory: Objects in projectile motion follow a parabolic path. This means the object's direction is constantly changing, even if its horizontal velocity remains constant.

Key points:

* Horizontal velocity: While horizontal velocity remains constant in projectile motion (ignoring air resistance), vertical velocity is affected by gravity.

* Acceleration: The constant acceleration due to gravity always acts downwards, affecting the vertical component of the object's velocity.

Therefore, projectile motion is not constant motion.