← 06-11 Pulley Quiz Solution

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Showing Revision 1 created 07/23/2012 by Amara Bot.

1. Let's look at a triple pulley. We'll first see have a triple pulley work.
2. We would wrap around this top pulley.
3. Go down around the bottom, wrap once more around the top
4. and then connect somewhere in the middle here.
5. Now we can see that the tension is pulling upwards one, two, three times.
6. The force diagram for that is well, the weight points down
7. and we have three arrows upwards each representing that tension.
8. Since the weight is a 1000 N, these each balance 1/3 of that and so we get a force of 333 N.
9. Of course the consequence is that your going have to pull three times further
10. than you did in the single case.
11. You can do similar thinking to solve for the quadruple pulley.
12. Now you may already be seeing a very amazing pattern emerging from this data.
13. Before we explicitly point it out there, why don' we calculate
14. one more method for lifting this rock by 1 m, let's look at an incline plane.