# Circular and Satellite Motion - Mission CG3 Detailed Help

 Suppose that you're at an amusement park and you get on a barrel ride. You stand on a platform with your back to the barrel wall. The barrel spins rapidly in a circle and the platform is suddenly dropped out from under you. Rather than falling, you and the wall remain 'pressed together.' This is best explained by the fact that ____.
 Definition of Inertia: Inertia is the property of an object that describes its natural tendency to keep on doing whatever it is doing.
 Inertia is simply the tendency of any object to keep on doing whatever it is doing. It is the natural tendency of an object to stubbornly maintain the same speed and the same direction that it has at any given moment. The direction that a barrel rider is moving at all points along the circle is in a straight line directed tangent to the circle. If all the forces on the rider were balanced, the rider would travel tangent to the circle. But the forces are not balanced. The wall pushes the rider towards the center of the circle so that the direction is continuously changing. The feeling of being pressed against the wall is simply the result of rider's tendency to go straight ahead. The wall is in the way and pushes back on the rider in a direction that is towards the center of the circle.
 Many students are confused by the notion of a centrifugal force. Centrifugal is an adjective that means outward. The incorrect conception is that a force pushes the riders in the outwards direction which presses them against the wall. But don't be fooled! There is no such outward force. Forces are not mysterious or ghostly. A force requires a person or thing to do the pushing or pulling. Can you think of any physical object which pushes you outward on a barrel ride? No. The wall is behind you and pushes you inward. The sensation of being pushed outward is simply the tendency that you have to move in a straight line at all times. This tendency carries you to the wall which then pushes you inward.