Work, Energy, and Power (4A) Practice Test

In a cycling ergometer test, two subjects each perform $300\ \text{J}$ of mechanical work on the pedals. Subject 1 completes the work in $10\ \text{s}$; Subject 2 completes the same work in $20\ \text{s}$. Using the definition of power $P = W/t$, which prediction is most consistent with the data?

During a physical therapy session, a patient lifts a $4.0\ \text{kg}$ dumbbell vertically upward by $0.50\ \text{m}$ at constant speed. Neglecting air resistance and taking $g = 9.8\ \text{m/s}^2$, apply the work–energy theorem to the dumbbell. Which statement is most consistent with the net work on the dumbbell?