The rate at which energy is expended. Your glass of milk is half a foot in front of you and one foot below your mouth. The weight of the glass times one foot. The weight of the glass time 0.5 feet The mass of the glass times one foot. The mass of the glass times 1.5 feet.
Work done is force times parallel component of displacement.
The force here is vertically directed weight and the vertical displacement is one foot. We had a demonstration in class where a thin strip of metal is put into a hot liquid and the end of the strip starts to bend down toward the liquid. The metal on the bottom was a special heat-seeking metal. The metal on the top was a special heat-seeking metal. The metal on the top expanded more when heated.