Circular Motion

Circular Motion

1. Centripetal force

   • Centripetal force is the force that keeps things turning in a circle.
     • Velocity is speed in a given direction, and acceleration is a change in velocity, so this means if you are moving round a circle at a constant speed you are constantly accelerating, because your direction is always changing. This acceleration is all focused towards the centre of the circle and is called centripetal acceleration.
       • Centripetal acceleration = velocity^2 / radius of the circle
       • Centripetal force between the centre and the object is suppled by the tension in the string if it is attached by a string. Tension in the string would increase if you span the object faster or increased its mass. Increasing the length of the string would cause tension to decrease, acceleration would then decrease.
         • In the example of a car going around a round about, friction between the tyres and the road is supplying the force.