You are testing a new amusement park roller coaster with an empty car with mass 123 kg. One part of the track is a vertical loop with radius 11.1 m. At the bottom of the loop (point A) the car has speed 27.1 m/s, and at the top of the loop (point B) it has speed 7.6 m/s. As the car rolls from point A to point B, how much work is done by the friction?