1. The problem statement, all variables and given/known data A train has a speed of v = 66.5 km/h. If the acceleration experienced by the passengers is to be less than 0.35 g, (g = 9.81 m/s2), find the smallest radius of curvature R acceptable for the track. 2. Relevant equations A=v^2/r a=(mv^2)/r 3. The attempt at a solution I tried putting 10.16 m/s^2 (added 9.81 + .35) for the acceleration and 18.4722 m/s for the velocity and putting it in the first equation to get 33.5848 m, however, this answer is close but not correct... I think the problem is, I don't understand what to do with the gravity? Is their another equation I am suppost to use or what? or am I only suppost to use .35 m/s/s as my acceleration? Please help, I cannot find any other simular examples in the text; the text only has examples involving tension and mass.