A roller coaster cart of mass \(M\) is driven at a constant speed \(v\) along a track that includes two circular sections. The first section is a loop-the-loop with a radius of curvature \(R\). The second section is a dip with a radius of curvature \(\{R\}/{2}\). The speed \(v\) is the minimum speed required for the cart to maintain contact with the track at the very top of the loop. Which of the following expressions represents the magnitude of the normal force exerted by the track on the cart when it is at the bottom of the dip?