1. The problem statement, all variables and given/known data A train moves along a circle with radius R = 2 km. The train accelerates with a constant rate, from v1 = 30 km/h to v2 = 100 km/h. It crosses SF = 1200 m during the acceleration. a) Find the time tF of the acceleration. b) What is the tangential acceleration aT of the train? 2. Relevant equations aT = Δv/Δt and anything relevant to non-constant displacement along a circle. 3. The attempt at a solution Although it seems pretty easy, I am unsure on how to use the formulas I have. For the first question, I calculated the average speed during the acceleration ((100-30)/2 + 30 = 65 km/h) and then the time it takes at this speed to cross 1.2 km (1 min 6s). Then I have a lot of different formulas for how to calculate the tangential acceleration, especially that one: aT = Δv/Δt Can someone please help me with how to use this formula in a problem? I would guess Δd is (100 - 30)⋅602 (in order to get a result in m/s) and Δt is 66s, am I right? Thank you very much in advance for your answers. J.