Question

The Gravitron is a common ride at festivals. It has a 4-meter radius circular platform surrounded by a fence that rotates at fast speeds. People stand with their backs to the fence. The floor suddenly drops away, and the reaction force to the centripetal force of the fence pushing in holds them tight against the fence. The force needs to be equal to their weight. With what velocity does the platform need to rotate.

Answer 1

The riders are pinned to the wall by a frictional force that acts inward, providing the necessary centripetal force. The only force acting on the riders is the frictional force.

Step-by-step explanation:

In order to hold the riders tight against the wall in the amusement park ride, a centripetal force needs to be exerted on them. This force is the reaction force to the centripetal force of the spinning barrel. It is the net force that acts toward the center of the circular path and keeps the riders moving in a circular motion.

In an inertial frame of reference, such as the Earth, the force that pins the riders to the wall is the frictional force between their bodies and the wall. As the riders move in a circular path, the frictional force acts inward, providing the necessary centripetal force to keep them in circular motion.

The only force acting on the riders in this scenario is the frictional force, which acts in the same direction as the centripetal force, toward the center of the circular path.