1. The problem statement, all variables and given/known data Initially collar is at rest with theta = 0. Find [tex]\dot\theta=f(\theta).[/tex] And find maximum theta reached. 2. Relevant equations I don't know if i allowed to use angular momentum about top-right frame corner as it's accelerating. But i definitely will need second Newton law:) 3. The attempt at a solution I know that there mg, N forces. But i can't figure out another force due to acceleration of the frame.