Solving for Fp: Bucket and Crank Problem with Unknown Forces

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Homework Help Overview

The discussion revolves around a physics problem involving a bucket hanging from a cord over a pulley, with a crank mechanism. The problem consists of two parts: determining the necessary length of the crank arm to lift the bucket in a specified time and identifying the maximum and minimum forces on the pulley axle.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between the force applied at the crank and the moments acting on the pulley. There are questions about how to express the acceleration in terms of the known variables and the implications for the forces on the pulley.

Discussion Status

Some participants have provided insights into the moments involved and the need to calculate acceleration, while others are seeking clarification on the formulas needed for both parts of the problem. The discussion is ongoing with various interpretations being explored.

Contextual Notes

Participants note that certain variables are known, while the forces on the pulley axle remain unknown. There is an emphasis on understanding the relationships between the forces and moments before proceeding to calculations.

cheesy
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I have a problem of two parts which I don't know what formulas to use. I would be greatful if someone could help me with it:

A bucket with the mass M is hanging in a cord with the length of L which in turn goes over a pulley with a diameter of D. The pulley has a crank with the length x. The force which is used at the end of the crank is F. How long must x be to make it possible to pull the bucket all the way up, L, in T seconds?



_____
/ / Fp \ F
II 0= I========
I \___/
I D
L I
I
IIIIIIIII
I M I
IIIIIIIII


The second part of the problem is to identify the maximum and minimum force (Fp-max & Fp-min) on the stand (that is the axle in the middle of the pulley).

L,M,D,F,T are known and Fp-max and Fp-min are unknown.

What formulas should be used to solve this problem?

/Cheesy
 
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The moment applied to the pulley, which is equal to the force F applied to the crank arm of length 'x', must equal the moment applied by the mass M at diameter, D.

The force applied by the mass M is the sum of its weight and force developed by the acceleration.

One must determine that acceleration in terms of distance, L, and during of acceleration, T.

http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html#c1
 
thanks a lot of help
 
the second question is easy when you know the first.
 

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