Question

A cable applies a vertical force to a crate with a mass of 70.0 kg. It first lifts the crate to a height of 12.0 m above the floor, and then lowers it back to the floor. What is the total work done by the force?

Answer 1

The total work done is zero.

Step-by-step explanation:

Given;

mass of the crate, m = 70.0 kg

height above ground through which the crate is lifted, h = 12.0 m

The only work associated in lifting and lowering this crate is gravitational potential energy.

Potential Energy during lifting = - mgh

= - 70 x 9.8 x 12

= - 8232 J

Potential Energy during lowering = mgh

= 70 x 9.8 x 12

= 8232 J

Total total work done by the force = - 8232 J + 8232 J = 0

Therefore, the total work done is zero.

Answer 2

Answer to the Question:

Step-by-step explanation:

In this case, the total work done by the cable is zero, since in the aforementioned problem, the work depends only on the starting and ending point, these two being equal. Keeping its gravitational potential energy equal.