The correct answer is: $1\text{ ft}$
Explanation
You are given $v=\sqrt{2gh}$. Solve for $h$ by squaring both sides and isolating $h$.
Steps:
- Square both sides: $$v^2 = 2gh$$
- Solve for $h$: $$h = \frac{v^2}{2g}$$
- Substitute $v=8\text{ ft/s}$ and $g=32\text{ ft/s}^2$: $$h = \frac{8^2}{2\times32} = \frac{64}{64} = 1\text{ ft}$$
Therefore the hammer was dropped from a height of $1\text{ ft}$.