A car of mass \(M\) travels at a constant speed \(v\) through the bottom of a circular valley of radius \(R\). At the lowest point of the valley, the magnitude of the normal force exerted by the road on the car is \(1.5Mg\). If the car were to travel through the same valley at a constant speed of \(2v\), which of the following would be the new magnitude of the normal force exerted by the road on the car at the lowest point?