Problem #2

Gravitational Potential

You are testing a new amusement park roller coaster with an empty car with mass 120 Kg. One part of the track is a vertical loop with radius 12.0 m. At the bottom of the loop (point A) the car has speed 25.0 m/s, and at the top of the loop (point B) it has speed 8.0 m/s. As the car rolls from point A to point B, how much work is done by friction?




Remember the idea of mechanical energy (Ke+U=E)!




Answer
-5400 j

(Young, Hugh, and Roger Freeman. University Physics. 12th. San Francisco: Pearson Education, 2008.)