54(111) 9. A differential pulley has two pulleys, with radius of 175 m and 190 mm respectively; what pull on the chain is necessary to raise 750 kilograms? (a) 296 N (b) 2,96 N (c) 29,6 N (d) 2,96 kN 10. In a wheel train, wheel A has a radius of 40 cm with a pinion of radius 10 cm, wheel B has a radius of 30 cm with a pinion of radius 15 cm, and wheel C has a radius of 50 cm. If it is desired to raise a weight of 22 400 newtons with a pull of 400 newtons, what must be the diameter of the drum on wheel C? (a) 21,28 cm (b) 7,14 cm (c) 14,28 cm (d) 17,14 cm 11. A journal is to carry a load of 4 tonnes, with a pressure of 1375 kilopascals; if the length of the journal is to be twice the diameter, what will be the diameter? (a) 12,1 cm (b) 15,0 cm (c) 21,5 mm (d) 1,5 cm 12. A weight of 2 500 kilograms is to be raised by a screw with a pitch of 10 mm; if the force to do the lifting is 40 newtons, at what distance from the axis of the screw should it be applied? Take g = 10m²/ (a) 100 cm (b) 10 m (c) 750 mm (d) 994,72 mm PTO