3. The scaffold S is raised hydraulically by moving the roller at A toward the pin at B.

3. The scaffold S is raised hydraulically by moving the roller at A toward the pin at B. If A is approaching B with a speed of 1.5 ft/s, determine the speed at which the platform is rising as a function of 0. The 4-ft links are pin-connected at their midpoint. 1.5 fus D 4 ft 0 S E B