+1832 In shaft BC he subtracted 2.4 - 1.2
how did he know that 2.4 is in oppisote direction of 1.2 ?
+33615 Presumably the motor is driving something (imagine, for example, there are belts over the discs going off to work some machinery). The discs are applying a force on whatever they are connected to (e.g. they are driving the belts), so, from Newton's third law, whatever is being driven is supplying a reaction force on the discs, opposing the drive.
Because it states that the torque of the motor is TOTAL 2.4 kN.m Tb = DIMINISHES it by 1.2
Tc removes 0.8
and Td diminishes it to Zero by .4 ....they all add up to the motor exerted torque 2.4
OK? Got it ? Yeah!
+1832 No I didn't get it .
My question was how did he know that the torque exerted by the motor is in opposite direction of Tb,Tc and Td ?
+33615 Presumably the motor is driving something (imagine, for example, there are belts over the discs going off to work some machinery). The discs are applying a force on whatever they are connected to (e.g. they are driving the belts), so, from Newton's third law, whatever is being driven is supplying a reaction force on the discs, opposing the drive.
