The Mystery of Pulleys: Answers to Your Burning Questions

[markyyyyyy]

Homework Statement

please can someone provide the answer to this question? see image attached I keep thinking B and C offer the same but i'm not sure?

Relevant Equations

n/a

 

[berkeman]

Welcome to the PF.

No, we cannot give you the answer and reasoning. That is for you to do. We can only offer tutorial help after you show your best efforts to work the problem.

So what have you learned about compound pulleys so far? Why does a compound pulley make it "easier" to lift an object? What is the tradeoff in using a compound pulley -- what do you have to do more of in order to make the lifting force less? How can you apply that fact to this problem?

Also, have you learned how to draw Free Body Diagrams (FBDs) yet in class?

 

[markyyyyyy]

my understanding is that the compound pulley makes it easier because the force required to move the weight is half due to the moveable pulley. i can also say that for every 1 metre of rope pulled, the weight will only move up 0.5m due. I'm confused between the diagrams B and C because to me they require the same effort / neither B or C is easier? They both have a fixed and moveable pulley, its only the anchor that is different, so which pulley makes it easier to lift a heavy weight?Thanks.

 

[DaveE]

i can also say that for every 1 metre of rope pulled, the weight will only move up 0.5m due.

Can you sketch this for each of the 3 examples? What does it look like before and after you've pulled 1m of rope?

 

[jbriggs444]

Problem Statement: please can someone provide the answer to this question? see image attached I keep thinking B and C offer the same but I'm not sure?
Relevant Equations: n/a

View attachment 247378

None of the choices provided are correct. [Unless one is very picky about the slant in the middle strand in C or less than appropriately picky about the slant in the left strand in A]