Idea: Centripetal Force

The NET force on a mass $m$ moving with velocity $v$ in a circle of radius $R$ is given by:$$F_c = \frac{mv^2}{R} = ma_c, \quad a_c = \frac{v^2}{R}.$$
The force points perpendicular to the mass’s velocity

Tip

Always remember that the centripetal force is the net force. Thus, when the situations are more complicated, make sure to always account for the direction of forces when adding them up to make the centripetal force. Furthermore, problems will often mention "loss of contact", and this usually means that the normal force is 0.