The roller coaster is a popular amusement ride developed for amusement parks and modern theme parks. LaMarcus Adna Thompson patented the first coasters on January 20, 1885. Roller coasters are dated back to as far as the 16th century, in Russia. These were sleds going over ice coverd wooded slides. Roller coasters keep advancing as technology does. The roller coasters now spin as they go over the track, and others lay you down as you ride. These are just some of many types of roller coasters that have been created over the past years. From the first roller coasters to the ones today, roller coasters keep advancing as time does. But one thing keeps all of the roller coasters the same and that is the physics of the roller coasters. All of the different types of roller coasters use the same type of physics (energy, circuits, magnetism and motion).
The positive and negitive g's are what make you feel heavier and feel lighter than your normal weight. They also make you feel like you could throw up. G's are short for gravity. So if you have 3 positive g's then you are 3 times more than your normal weight. This website explains more about the g's. http://dsc.discovery.com/videos/time-warp-roller-coaster-science.html