# Bucket and crank

1. Sep 30, 2006

### cheesy

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

2. Sep 30, 2006

### Astronuc

Staff Emeritus
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

3. Oct 1, 2006

### cheesy

thanks a lot of help

4. Oct 1, 2006

### cheesy

the second question is easy when you know the first.