Calculating Net Work Done on a Man in a Wheelchair Climbing a Slope

[Matriculant]

Homework Statement

A man in a wheel chair is being pushed up a slope, for a distance of 10 metres. He is moving at a constant velocity. What is the net work done when he reaches the top of the slope?

Homework Equations

W = FX

The Attempt at a Solution

I just seem to have forgotten something basic.

The answer stated on the memo is that no work has been done, as

W = FX ( F = 0 due to constant velocity )

However, the thing that my mind can't seem to comprehend as of late, is that the total mechanical energy of the system has increased as the object has gained gravitational
potential energy.

Therefor, in my mind, the force that is being used to overcome the force of gravity is doing
work, as the body is gaining energy.

Essentially, I am at the moment believing that Mechanical Energy Final - Mechanical Energy Initial = Work Done

I'm quite lost. If I have misunderstood the concept of work, then I would gladly take a point to the right direction.

Thanks :)

 

[tiny-tim]

Welcome to PF!

Hi Matriculant! Welcome to PF!

A man in a wheel chair is being pushed up a slope, for a distance of 10 metres. He is moving at a constant velocity. What is the net work done when he reaches the top of the slope?
…
The answer stated on the memo is that no work has been done, as

W = FX ( F = 0 due to constant velocity )

However, the thing that my mind can't seem to comprehend as of late, is that the total mechanical energy of the system has increased as the object has gained gravitational
potential energy.

Therefor, in my mind, the force that is being used to overcome the force of gravity is doing
work, as the body is gaining energy.

This is a trick question …

you think you're being asked what work is being done by the person pushing,

but actually it's asking for the net work done, ie the work done by all the forces …

gravity is one of those forces, so the answer is zero

(the question doesn't ask you to apply the work energy theorem … it it did, you would have to say that potential energy is defined as minus work done by a conservative force, and therefore can go either on the work side of the equation, or on the energy side … but not both!)