FB Diagram Problem: Is My Sketch Correct?

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The discussion centers on the correctness of a free body diagram (FBD) related to a pulley system. The initial sketch for the bucket is confirmed as correct, while the FBD for the pulley is deemed incorrect due to misaligned forces and missing support forces. It is established that the tensions T (orange) and T (blue) are equal if the pulley is frictionless and massless. The necessity of the pulley’s FBD is questioned, as it primarily serves to redirect force rather than contribute additional forces. Ultimately, the focus shifts to the FBD for the hand providing the force F, which is deemed more relevant for understanding the system.
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Homework Statement



freebd.jpg


Homework Equations



Is my sketch(illustration) and fbd correct? Is T(orange) = T (blue)?

The Attempt at a Solution

 
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chemic_23 said:

Homework Statement



freebd.jpg


Homework Equations



Is my sketch(illustration) and fbd correct?
Yes, for the bucket. The fbd of the pulley is not correct, your forces are not in the right direction, and there is an additional force on the pulley not shown at the point where it is supported. But don't worry about the fbd of the pulley, since you don't need that one.
Is T(orange) = T (blue)?
Yes, as long as the pulley is frictionless and massless.
 
can you give me the correct fbd for the pulley? I just want to know.
 
I think fbd: (pulley) should be fbd: (hand)? is it correct?
 
As Jay mentioned, you don't need the force diagram for the pulley since all it does in this question is change the direction of a force. In this case, a force F causes a tension T in the rope, which is redirected to pull the block upwards.

Perhaps what you need is a force body diagram for the hand/thing that provides the force F.
 
chemic_23 said:
can you give me the correct fbd for the pulley? I just want to know.
jaseh86 is correct. If you want to know the free body diagram of the pulley,which must be anchored to a table or such, you have T acting to the right, and T acting down (the rope tension), and for equilibrium, you must have the table supporting reaction force, R, acting up and to the left at a 45 degree angle thru the center of the pulley (R= T/cos45 = 1.414T). But don't fool with it.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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