(a) Calculate the force (in N) the woman in the figure below exerts to do a push-up at constant speed, taking all data to be known to three digits. (You may need to use torque methods from a later chapter.) N 0.89 m m = 62 kg CG W 1.49 m W Freaction (b) How much work (in J) does she do if her center of mass rises 0.280 m? (c) What is her useful power output (in W) if she does 24 push-ups in 1 min? (Should work done lowering her body be included? See the discussion of useful work in Work, Energy, and Power in Humans.)