Question

If a crane worker lifts a crate with a mass of 120 kg from the ground to a shipping container that is 30 m off the ground, by how much has the worker increased the gravitational potential energy of the crate, recalling that g=9.8m/s²?

a. 35,400 J
b. 39,600 J
c. 42,000 J
d. 47,040 J

Answer 1

The worker has increased the crate's gravitational potential energy by 35,400 joules by lifting it 30 meters off the ground with the given values of mass and gravitational acceleration.

Step-by-step explanation:

To calculate the increase in gravitational potential energy (GPE) of the crate that the crane worker lifts, we use the formula GPE = mgh, where:

m is the mass of the object (in kilograms),

g is the acceleration due to gravity (in meters per second squared),

h is the height to which the object is lifted (in meters).

In this case:

m = 120 kg

g = 9.8 m/s²

h = 30 m

Plugging these values into the equation yields:

GPE = (120 kg) × (9.8 m/s²) × (30 m) = 35,400 J

Therefore, by lifting the crate to a height of 30 m, the worker has increased the crate’s gravitational potential energy by 35,400 joules.