Centrifugal Force

Some people thought that an object moving in a circle would experience the centripetal force acting from the object towards the centre of the circle and the centrifugal force acting from the object away from the centre of the circle.

They thought this because if you sit on a roundabout as it spins it feels like you are being thrown off backwards.

If someone was watching from the side they would see you try and move in a straight line but be pulled in a circle by the roundabout.