Hi, 1. The problem statement, all variables and given/known data A horizontal smooth disk of radius R rotates around its axis with constant speed ω. At t=0 a mass m is thrown at speed v0 (in the lab's frame of reference) towards the center of the disk. I am asked to write down the velocity vector of the mass in the lab's frame of reference and in the disk's. It is stated that in both cases the origin is at the center of the disk. 2. Relevant equations 3. The attempt at a solution Primarily, won't the mass's acceleration in the lab's frame of reference be: a = -2ω x v' - ω x (ω x r), where |v| = v0 - ωr? Won't the mass's velocity in the disk's frame of reference be: v = [ωr]θ + [dr/dt]r? I could truly use some guidance here. Thanks!