where 
is the radius of the circle, 
is the mass of the particle and 
is its angular speed. [P2.6, P3.2]
on: a particle in uniform circular motion
is: the force which is necessary to maintain the uniform circular motion. [P2.3]
is directed: towards the centre of the circle. [P2.3]
has magnitude: where is the radius of the circle, is the mass of the particle and is its angular speed. [P2.6, P3.2]
Copyright 1997, The Open University