A weightlifter works out at the gym each day. Part of her routine is to lie on her back and lift a 41kg barbell straight up from chest height to full arm extension, a distance of 0.45m . Part A: How much work does the weightlifter do to lift the barbell one time? Part B: If the weightlifter does 23 repetitions a day, what total energy does she expend on lifting, assuming a typical efficiency for energy use by the body? Part C: How many 500 Calorie donuts can she eat a day to supply that energy?