Roller Coaster Forces
Roller Coasters are great for giving you the feeling of weightlessness, heaviness, and jerkiness. Newtons laws of motion help us understand why we feel these sensations. A clothoid loop is most responsible for the feelings of weightlessness and heaviness on a roller coaster ride.
When going on this loop your direction is constantly changing. The reason why you are accelerating around the loop while always changing direction is because of unbalanced forces.
Before you understand why we feel weightless and heavy, we need to understand the forces that are acting on the rider. When going on the loop there is a gravitational force and a normal force. The gravitational force is always directed down. The normal force is always perpendicular to the track. The gravitational force never changes, it is always the same amount of force going straight down. The gravitational force is not what you feel when riding on a roller coaster. The normal force is what you feel. The amount of normal force you have changes while going around the loop. When the normal and gravitational forces are balanced you don’t feel any weightlessness or heaviness. At the top of the loop the rider feels weightless because there is little normal force. The normal force at the bottom of the loop is large so the rider feels heavy. The rider is not acctually ever getting heavier or lighter. The seat on the roller coaster is responsible for the normal force. At the top of the loop the seat is not applying much normal force to the rider so the rider feels weightless. At the bottom of the loop the seat is applying a lot of normal force to the rider making the rider feel heavy. Thats whats makes roller coasters so fun!