1. The problem statement, all variables and given/known data: A child of mass 40.0 kg is in a roller coaster car that travels in a loop of radius 7.30 m. At point A the speed of the car is 15.0 m/s, and at point B, the speed is 15.6 m/s. Assume the child is not holding on and does not wear a seat belt. What is the force (in N) of the car seat on the child at point B? (Enter the magnitude.) 2. Relevant equations Fc = [(mv^2)/r] Fc = ma 3. The attempt at a solution: I solved (a) and (c). I solved (a) by inserting the mass, speed, and radius into the equation [(mv^2)/r] and subtracting by (mass*gravity). My equation for (b) was [(mv^2)/r * cos30] - mg = [(40*(15.6^2)/7.3*cos30) - (40*9.8) = 762.8 N. That was incorrect. What's improper about my equation?