History of Roller Coasters/1600s First roller coasters were built in Russia in the 1600’s. Steep ice slides slowed with sand.
1800’s French tried to make a coaster with ice but because of the warm climate he had to use a waxed wooden slide and wooden wheel sleds. Because of accidents, tracks were built to keep the sleds in line.
Roller coasters in the U.S.A. Roller coasters began on railroads that would use the tracks for thrill seekers as early as 1872 in Pennsylvania. Based on this idea, amusement parks began adding coasters like the one at Coney Island in Brooklyn, NY
Today… Roller coasters are much more sophisticated and most of this sophistication in design is due to societies more complete understanding of physics.
Gravity… The driving force of the roller coaster. Remember, acceleration due to gravity occurs at 9.8 m/s2 straight down toward the center of the Earth.
Potential Energy… The first hill (also referred to as the lift hill) is the tallest in the entire ride. As the coaster is pulled to the top, it is gaining potential energy. The higher the lift, the greater the potential energy. PE = mgh
Velocity and Kinetic Energy Once the coaster begins its descent from the lift hill, the velocity increases, which causes the train to gain kinetic energy. The faster the coaster moves, the greater the kinetic energy the coaster contains. K = 1/2mv2 What do you think happens to the coasters kinetic energy as it climbs back up the track?
Conservation of Energy… Energy cannot be created or destroyed, it can be converted from one form to another. Ideally, in a roller coaster all energy is conserved through conservative forces, such as gravity. When the coaster accelerates down the lift hill, potential energy is converted into kinetic energy and when the train ascends another hill, kinetic energy is converted into potential energy again. This conservation of MECHANICAL energy continues through the whole ride. Etot = PE + KE Ei = Efor total initial mechanical energy equals the total final mechanical energy. Theoretically, after the initial input of energy to carry the train up the lift hill, the roller coaster simply coasts through the rest of the ride.
Friction Friction opposes motion by working in the opposite direction. Friction is the main cause of energy leaks in in the system. Friction is a nonconservative force which causes a change in the total mechanical energy. What are the elements of friction with a roller coaster? These elements slow down the coaster and create both heat and sound. This is most evident at the end of the ride as all the remaining kinetic energy is taken out of the system through brakes. Because of the energy leaks due to friction, each successive hill or loop on a roller coaster must be shorter than all the hills previous to it.
Centripetal Acceleration Centripetal acceleration is felt by coaster passengers on the curves and loops of the coaster. CA points toward the center of the circular path of the train, but is felt by passengers as a force pushing them to the outer edge of the circular path. The “centrifugal force” you feel is actually your body’s inertia, or its resistance to the coasters change in direction: your body wants to stay in a straight line and attempts to do so as the train turns. CE = v2/r (r = the radius of the circle in m) Therefore, the higher the train’s velocity, the greater the centripetal acceleration. The smaller the curve of the path being traveled, the greater the centripetal acceleration.