A CANNONBALL IS FIRED FROM THE TOP OF A HIGH MOUNTAIN AND BEHAVES LIKE A PROJECTILE (NO WIND RESISTANCE) AS IT TRAVELS TO THE GROUND FAR BELOW. What can you say about the horizontal velocity of the cannonball?
a. It is constant.
b. It depends on the speed that the cannonball was fired.
c. It does not depend on the speed that the cannonball was fired.
d. It increases 10 m/s every second (10 m/s2).
e. It depends on gravity

Body thrown at some angle above or below the horizontal plane such that angle is grater than 0 degrees and lesser than 90 degrees is called Projectile.

The motion in which a body has constant horizontal component of velocity

but changing vertical component of velocity is called projectile motion. Every projectile body has PROJECTILE MOTION.

The Vertical Velocity will decrease during upward motion and increase during downward motion, by the factor,

Where,

Vf = final velocity

Vi = initial velocity

Theta is the angle at which projectile is fired

g is acceleration due to gravity

t is time

HORIZONTAL VELOCITY remains constant. According to Newton's 1st Law object in motion stays in motion until a force acts on it. There are no forces acting on a projectile in the horizontal direction (neglecting air resistance), therefore the velocity is constant.

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.

truck y has a greater velocity than truck x.