How does one calculate centripetal force?

Consider the standard equation for force, F = ma. In a centripetal system, the acceleration a is given by a = v^2/r. Plugging this in to the equation for force yields F = mv^2/r; hence to calculate centripetal force, we need to know the mass m (in kg) of the object in centripetal motion, it's velocity in meters per second, and the radius of its motion in meters. Putting these units together, we end up with the centripetal force in kgm/s^2, or Newtons.