You squeeze into the molded plastic seat and pull the padded bars down so they fit snug against your shoulders. The attendant comes by and pushes on the bars to make sure they are locked into place. Then the cars of the roller coaster begin to move out of the station, going up and up, until you feel that you can touch the sky. Suddenly, with a lurch, your car reaches the top. As it crests the hill and starts down the other side, you can feel it begin to pick up speed. Now you are flying down the track, up smaller hills, through loop-de-loops, upside down and twisting all around. You scream as the roller coaster rounds a curve in the track and you are pushed to one side. Finally, the coaster begins to slow down. It comes to a stop back at the station, and you are released. What a ride!

If you like to ride roller coasters, the description above probably sounds familiar. But did you know that roller coasters aren't just thrill rides? Actually, roller coasters are examples of the laws of physics in operation. Roller coasters are pulled to the top of the highest hill, then released. A coaster has potential energy as it is pulled to the top, but this changes to kinetic energy as the coaster begins its descent. Gravity and friction control the rest of the ride. Why don't the cars of a roller coaster fly off the track? Why don't the passengers fly out of the cars? How high can the first hill of a roller coaster be? What physical laws determine how many hills, curves, and loops a roller coaster track can have? You can find answers to these questions in this WebQuest.