In volleyball gravity effects everything, the players, net, but especially
the ball. Without gravity the ball would never come down. It would continue in
the same direction in which the force was implied. Projectile motion involves
gravity. Gravity is what makes the ball return to the ground.
In this picture above you see a ball and the path it is traveling. The ball
resists gravity (Gravity is always effecting it though) and moves in a
horizontal, upward motion until gravity slows it down. The ball then will fall
to the nearest solid.
