1. The problem statement, all variables and given/known data If the car is given an initial speed of 4.0 m/s, what is the largest value that the radius R can have if the car is to remain in contact with the circular tract at all times? See the attached file (named: car.pdf) for the drawing. 2. Relevant equations PE=mgh ----> Formula for Potential Energy KE=(1/2)mv² ----> Formula for Kinetic Energy Fc=mv²/R ----> Formula for Centripetal Force 3. The attempt at a solution My initial attempt was to assume that the car has zero velocity at the top of the circle. However this is not true, since the car should "remain in contact with the circular tract at all times". This is an even problem from my textbook, so no answer is given in the back. By the way, I am referring to "Physics 6th Edition" by Cutnell & Johnson. Thank you for helping!