I'm trying to figure out why potential energy decreases in this situation
ΔU = FΔy
The Attempt at a Solution
If I define up to be positive, and ΔU = FΔy. In this picture, force is pointing down (so it is negative) and the height decreases so Δy is negative.
Then ΔU = (-F)(-Δy) = FΔy. So then change in electric potential energy is positive, which means it should be increasing. But in the picture it says that U decreases.
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