Tip:
Highlight text to annotate it
X
Well, the best answer is mgh--in fact, that's the only answer. Let's see why.
Well, let's do a diagram of for example this bucket--there's mass m and weight mg.
The force you exert must balance mg, so actually the magnitude of this force
that you're pulling on the bucket with must be equal to mg.
You'll know that this is the equation which describes work and this case,
your force is mg and that's upwards which is also the direction of the Δx,
but here Δx becomes h--so that's how we get that answer.