PRACTICE IT Use the worked example above to help you solve this problem. A woman of mass m58.7 kg sits on the left end of a seesaw-a plank of length L = 4.61 m, pivoted in the middle as shown in the figure. (a) First compute the torques on the seesaw about an axis that passes through the pivot point. Where should a man of mass M 69.9 kg sit if the system (seesaw plus man and woman) is to be balanced? 1.936 (b) Find the normal force exerted by the pivot if the plank has a mass of mpl 12.6 kg. 1383 IN (c) Repeat part (a), but this time compute the torques about an axis through the left end of the plank.