(((Since my pre-finals test is Friday, this Friday, I decided to skip the energy questions and go over the basic dynamic energy-less stuff since I'll never get enough practice on energy on time. Please excuse me. I'll return to solve my energy-spring topic before that at a later occasion. ))) http://img202.imageshack.us/img202/2360/hhheyn.jpg [Broken] I'll quote the question: "Controlling the rotation of shaft OA around point O, in the described structure, is performed by analyizing the horizontal motion of hydraulic cylinder shaft piston H, in the described position. The angle, theta, equals 66 degrees. The speed of point B (Vb) is 3 meters per second, and OA is at horizontal position. --- Now, The manual shows Va pointing vertically down (no angle to the Y axis). My question is how am I supposed to know this is the case? That this is really the direction of Va's velocity?