REVERSING PULLEY ROTATION  ANSWER
V. Ryan © 201017
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1. A system of four pulley wheels are set up as shown in the diagram above. The driver pulley rotates in an anticlockwise direction. In what direction does the output pulley wheel revolve ? Look at the animation below. The final output of pulley F is a clockwise movement. 

2. If pulley ‘A’ (driver) rotates at 60 rpm what is the output rpm at ‘F’. 

To answer the question spit the pulleys into pairs
and work out the velocity ration of each pair. Treat the pairs of
pulleys as separate questions. 

Pulley wheel A has an rpm of 60. Pulley B is larger and so revolves at a lower rate than A. This means that the rpm of A is divided by the ratio of 2. 

Pulley wheel C has the same rpm as pulley B because they form a compound pulley. Pulley D is larger and so revolves at a lower rate than C. This means that the rpm of C is divided by the ratio of 1.2 

Pulley wheel E has the same rpm as pulley D because they form a compound pulley. Pulley F is smaller and so revolves at a higher rate than E. This means that the rpm of E is multiplied by the ratio of 1.3 



