Question

Which component of velocity of a projectile is constant?

Answer 1

Hint By Newton's first law of the motion statement, the which component of the velocity of a projectile is constant can be determined. During the projectile motion, the object will have two velocities, one is horizontal velocity and the other is vertical velocity.

Complete step by step solution
Newton’s first law of motion states that the object or any body is in state of rest or in the uniform motion, the object or the body will remain its same rest position or the same uniform motion unless an external force will act on the object or the body which are in state of rest or in the uniform motion.
When the body or the object is subjected to the projectile motion, then the body or the object will experience the two velocities because in the projectile motion, the object or the body is travelling in some angle with the horizontal plane so that the velocity of the object or the body is separated as the vertical component and the horizontal component.
In these two velocity components, one of these two velocity components is constant. The velocity of the horizontal component of the projectile motion is constant because there is no external force which acts on the horizontal component of the velocity, but the external force acts on the vertical component of the velocity. The external force which acts on the vertical component of the velocity is gravitational force.

Note The horizontal velocity of the object or the body is constant through all the projectile motion. The horizontal component of the velocity of the object is constant from the starting point to the end point. But the vertical velocity is changed in the projectile motion.