## Question:

Rod AB is attached to a collar at A and is fitted with a wheel at B that has a radius r= 15 mm. Knowing that when $\theta= 60°$ the colar has velocity of 250 mm/s upward and the speed of the collar is decreasing at a rate of $150 mm/{ s }^{ 2 }$, determine (a) the angular acceleration of rod AB, (b) the angular acceleration of the wheel.