posted by sandhu on .
Two men are carrying a 9.00-m telephone pole that has a mass of 115 kg. If the center of gravity of the pole is 3.00 m from the right end, and the men lift the poles at the ends, how much weight must each man support?
The man closest to the center of gravity must lift 2/3 of the pole's weight. The other guy lifts 1/3 of the weight. You can prove that with a moment balance.
The pole's total weight is 115 x 9.8 Newtons.
You take it from there
Use the formula for center of mass.
(∑ distance * mass) / total mass = center of mass
The masses are what each man is holding, the distance is where each man is from some origin. If you set the origin on one of the men, his distance * mass is 0. Since we know the center of mass is 6, we can solve for the mass. 2/3 for the man on the right and 1/3 for the man on the left.