# Homework Help: Stresses and forces

1. Apr 7, 2014

### raymanmusic

1. The problem statement, all variables and given/known data
https://dl.dropboxusercontent.com/u/11241083/tractor.png [Broken]
How do I calculate reaction forces at A and B? We pull with a force F2 = 300 N on the steel wire. The steel wire goes two and a half times around the axel wheel.

$d = 38 mm$

$D = 200 mm$

$a = 100 mm$

$b = 120 mm$

$\sigma_{w} = 256 \frac{N}{mm^{2}}$

$K_{t} = 1.5$

$\eta_{k}=0.7$

$\mu=0.2$

$F_{A} = 13.3 kN$
$F_{B} = 6 kN$

Last edited by a moderator: May 6, 2017
2. Apr 7, 2014

### SteamKing

Staff Emeritus
What have you tried? This seems to be a very straight forward problem.

Why don't you try something that can be checked and discussed?

Hint: Pretend the power take of shaft (a-b-d) is a beam with two supports and the load from the sheave is cantilevered over the end of this beam.

3. Apr 7, 2014

### raymanmusic

What is the force at the end of the shaft? Is it the same as F2=300N? I sum moment at point B to try to find reaction force at A.
https://dl.dropboxusercontent.com/u/11241083/New%20Document20140407191616593.pdf [Broken]

Last edited by a moderator: May 6, 2017
4. Apr 7, 2014

### SteamKing

Staff Emeritus
Look at the left figure, the one showing how the line goes around the sheave. You are given F2, so make a FBD of the sheave to see what load the shaft sees.

Last edited by a moderator: May 6, 2017