21. One of the most common mechanisms .s the slider-crank (see figure). The length or A3 is d and the length of DB is 1'. These lengths are fixed. The distance AD is y and it can change. (a) Exoress the angular velocity of 0|: (0') in terms or the angular velocity of AB ('9' 'J. (5) Express the horizontal velocity of the slider (point A) in terms of the angular velocity of DB (6')