A motorbiker (m = 86.2 kg) decides to join a travelling circus during the summer months to "see the world". He volunteers to drive a motorbike (m = 104 kg) inside a spherical metal cage (radius = 10.0 m) for entertainment. a. While driving horizontally around the middle of the cage, he completes 25 loops in one minute. Determine the coefficient of friction he needs between his tires and the cage so that he doesn't slide down. b. He then turns so that he eventually rides around the cage vertically at 16.5 m/s. What force is the motorbike being pushed with at both the top and bottom of the cage to allow him to do this?