1. The problem statement, all variables and given/known data If a high jumper can clear a 2m bar on Earth, how high is the bar he can clear on the moon assuming it is done under the same conditions as on the Earth. Acceleration due to gravity on the moon is 1.7 m/s^2. 2. Relevant equations GPE = mgh 3. The attempt at a solution I set mgh on Earth equal to mgh on the moon as the athlete exerts the same starting energy transfer. I got a factor of 5.8 giving the bar on the moon at 11.6m. However, the mark scheme says the athlete lifts his COM 1m on Earth. I have no idea how you are suppose to know this? I get that the COM goes under the bar but what makes it half the height of the bar? This is a proper past exam question and what I have put in the question is all they give you! Please help. Thanks.