The system shown is initially at rest when the bent bar starts to rotate about the vertica...

The system shown is initially at rest when the bent bar starts to rotate about the vertical axis AB with constant angular acceleration α0 = 3 rad/s2. The coefficient of static friction between the collar of mass m = 2 kg and the bent bar is μs = 0.6, the angle of the bend in the bar is θ = 30°, and the collar is initially at d = 70 cm from the spin axis AB.

Assuming the motion starts at t = 0, determine the time at which the collar starts to slip relative to the bent bar.

Figure P3.143