Consider the motion of the slider-crank linkage shown in Fig. 10.3, and assume the crank
(1) drives the slider (3). Therefore, the motion of the crank will be known completely, and because it is in pure rotation about point A, this means only its angular velocity (ωcrank) and angular acceleration (αcrank) must be specified. Pure rotation means that every point on this element of the linkage moves in a circle about the point A.