8. the potential energy of an apple is 6.00 j...

# Explanation: ## Step1: Recall potential - energy formula The formula for gravitational potential energy is $U = mgh$, where $U$ is potential energy, $m$ is mass, $g$ is the acceleration due to gravity ($g= 9.8\ m/s^{2}$), and $h$ is height. We need to solve for $m$. ## Step2: Rearrange the formula for mass From $U = mgh$, we can get $m=\frac{U}{gh}$. ## Step3: Substitute the given values We know that $U = 6.00\ J$, $h = 3.00\ m$, and $g = 9.8\ m/s^{2}$. Substituting these values into the formula $m=\frac{U}{gh}$, we have $m=\frac{6.00}{9.8\times3.00}$. ## Step4: Calculate the mass $m=\frac{6.00}{29.4}\approx0.204\ kg$. # Answer: $0.204\ kg$