1. The problem statement, all variables and given/known data A weightlifter works out at the gym each day. Part of her routine is to lie on her back and lift a 44 kg barbell straight up from chest height to full arm extension, a distance of 0.54 m. 2. Relevant equations If the weightlifter does 24 repetitions a day, what total energy does she expend on lifting? Assume 25 % efficiency. 3. The attempt at a solution I looked at it, and could only see that the only change in energy is work. Work is 230J per repetition. I tried multiplying 230J by 24 in order to get the answer, but it was not correct.