To determine the horizontal distance the ball travels when it hits the ground, we need to find the value of \( x \) when the height \( h(x) \) is equal to 0 (the ground level).
The equation given is:
\[ h(x) = -\frac{1}{2} x(x - 20) \]
Setting \( h(x) = 0 \):
\[ -\frac{1}{2} x(x - 20) = 0 \]
This equation can be factored as follows:
\[ -\frac{1}{2} x(x - 20) = 0 \]
By setting each factor equal to zero:
- \( x = 0 \) (This is when the ball is kicked from the ground.)
- \( x - 20 = 0 \) (This gives \( x = 20 \).)
Thus, when \( x = 20 \) feet, the ball will hit the ground.
The horizontal distance the ball travels when it hits the ground is:
\[ \text{20 feet} \]