An object moving along a circular path requires a force known as centripetal force to continue moving in along the path. In the absence of this force, the object would move in a direction tangent to the circle at the point where the force is no longer present.
In kart racing, when a driver makes a turn, the kart is forced to move along a path that is not a straight line. The centripetal force that results in this is provided by the force of friction between the kart and the ground. The magnitude of centripetal force is given by the equation `F = m*v^2/r = m*r*(4*pi^2)/T^2` .
If the driver moves along a circular path with a larger radius, a smaller centripetal force is required and the driver can move at a faster speed while maintaining control. The frequency, period and radius have to be kept in consideration while driving to ensure that there is sufficient friction to allow the turn being taken.