Question

question 12 of 29
if a crane worker lifts a crate with a mass of 120 kg from the ground to a shipping container that is 30 meters off the ground, by how much has the worker increased the gravitational potential energy of the crate? (recall that g = 9.8 m/s²)
a. 18,180 j
b. 46,720 j
c. 29,950 j
d. 35,280 j

Explanation:

Step1: Recall the formula for gravitational potential energy

The formula for gravitational potential energy is $U = mgh$, where $m$ is the mass, $g$ is the acceleration due to gravity, and $h$ is the height.

Step2: Substitute the given values

We are given that $m = 120\ kg$, $g=9.8\ m/s^{2}$, and $h = 30\ m$. Substituting these values into the formula $U=mgh$, we get $U=120\times9.8\times30$.

Step3: Calculate the result

$120\times9.8\times30=(120\times9.8)\times30 = 1176\times30=35280\ J$.

Answer:

D. 35,280 J