In projectile motion, what remains constant during the flight of the object?

In projectile motion, the horizontal velocity of an object remains constant throughout its flight, assuming there is no air resistance. This is due to the nature of projectile motion, where the only force acting on the object in the horizontal direction after launch is gravity, which does not affect horizontal motion. Therefore, the initial horizontal velocity remains unchanged as the object moves forward, resulting in a uniform horizontal motion.

In contrast, vertical velocity is influenced by gravity, causing it to change continuously throughout the flight. The height of the object also varies as it moves up and then down in its trajectory. While weight remains constant (as it is determined by the mass of the object and the gravitational force acting on it), the velocity specifically refers to the velocity's different components (horizontal and vertical), hence the emphasis on horizontal velocity being constant is the key point regarding the object's motion.