7. Joe, a pole-vaulter, is holding a vaulting pole parallel to the ground. The pole is 5 m long. Joe grips the pole with his right hand 10 cm from the top end of the pole and with his left hand 1 m from the top end of the pole. Although the pole is light (its mass is only 2.5 kg), the forces that Joe must exert on the pole to maintain it in this position are large. How large are they? (Assume that Joe exerts only vertical-up or down-forces on the horizontal pole and that the center of gravity of the pole is located at the center of its length.) 10. A barbell is loaded with two 20 kg plates on its right side and two 20 kg plates on its left side. The barbell is 2.2 m long, and its unloaded mass is 20 kg. The two 20 kg plates on the right side are locked in place at 35 cm and 40 cm from the right end of the bar. The two 20 kg plates on the left side have slipped. One is 30 cm from the left end of the bar, and the other is 20 cm from the left end of the bar. Where is the center of gravity of this barbell with the four plates? om 20 cm 35 om Right 22m