1. The problem statement, all variables and given/known data A car of mass m takes off from rest around a circular track of radius r . Speeding up at a constant rate, the car takes t seconds to go around the track once. What is the magnitude of the net force acting on the car at the end of the trip? 2. Relevant equations a_rad = 4*pi^2*R/T^2 F=ma 3. The attempt at a solution I simply used the acceleration formula and plugged it into N2L to get (4*pi^2*r*m)/t^2, but it's not right. Could someone please tell me what I am doing wrong and how to fix it.