I am able to do (i) and (ii), but (iii) confuses me since I'm not even sure what point B is supposed to be. It says it's a point on the link 3 but it doesn't look like it's connected by a joint, and instead link 3 is just fixed 90 degrees with the slider.
3. A four-bar inverted crank-slider mechanism is shown below. Node A is the R joint between the input link and the coupler. B is a point on the coupler (link 3). Using a proper velocity scale and draw a velocity diagram. Determine (i) the angular velocity of link 4 and the relative velocity of link 3 to link 4, (ii) the linear velocity of point B by means of the velocity image theorem or the relative velocity diagram, (iii) the Coriolis acceleration a344, and (iv) the relative sliding acceleration a3/44. [20]
B
Scale: 1:10 2=150 rad/s (ccw)