4/125 The power unit A of the tractor-scraper has a mass of 4 Mg with mass center at G1. The fully loaded trailer-scraper unit B has a mass of 24 Mg with mass center at G2. Positioning of the scraper is con- trolled by two hydraulic cylinders EF, one on each
4/126 An automatic window-positioning system for a greenhouse is shown in the ?gure. Window OA has a mass of 50 kg with mass center at G. A motor (not shown) drives the gear C, which in turn moves the positioning rack AB. For the window position shown, determine the motor torque M which must be supplied to the pinion C. Neglect the weight of bar AB.
