Question

multiple - choice question
which 10 kg (22 pounds) box would hurt the most if it fell on you?
the box 5 meters (16.4 feet) high
the box 3 meters (9.8 feet) high
rewatch

Explanation:

Step1: Recall the concept of potential energy

The potential energy of an object near the Earth's surface is given by $U = mgh$, where $m$ is the mass, $g$ is the acceleration due to gravity ($g\approx9.8m/s^{2}$), and $h$ is the height. The greater the potential energy of the box before it falls, the more energy it has to transfer upon impact, and the more it will hurt.

Step2: Compare the heights

We have two cases with the same mass ($m = 10kg$). The first box is at a height $h_1=5m$ and the second box is at a height $h_2 = 3m$. Since $U=mgh$ and $m$ and $g$ are constant, the box with the greater height will have more potential energy.

Answer:

The box 5 meters (16.4 feet) high