Final answer:
The range of a horizontally launched projectile depends on its initial horizontal velocity. The greater the velocity, the longer the range. Mass or weight does not affect the range when air resistance is ignored.
Step-by-step explanation:
The range of an object launched horizontally primarily depends on the object's initial horizontal velocity and the height from which it is launched. The greater the initial horizontal velocity, the greater the range of the projectile. The effect of gravity defines the time the object will be in flight, thereby affecting its range, but the weight or mass of the object does not change the range in the absence of air resistance. Moreover, the launch angle plays a significant role in determining the range; however, for horizontally launched objects, this is a constant of 0 degrees. The optimal launch angle for maximum range, in a vacuum or conditions where air resistance is negligible, is 45 degrees, but this does not apply to horizontally launched projectiles.