- #1
Calpalned
- 297
- 6
Homework Statement
A window washer pulls herself upward using the bucket-pulley apparatus shown in the figure. How hard must she pull downward to raise herself slowly at constant speed? The mass of the person plus the bucket is 71kg .
Homework Equations
F of gravity = mg
F effort = mg/2
The Attempt at a Solution
I found out later that using a pulley reduces the force to half, so I did Force = mg/2 which is the correct answer. I am confused because according to this website http://www.explainthatstuff.com/pulleys.html and http://www.ehow.com/how-does_5231254_much-weight-pulley-off_.html , two wheels are needed for a reduction of force by one half. There is only a single wheel on the pulley for the window washer.
In other words, the force to pull the window washer up should be equal to to her weight (mg) and not half of that. Did I misread something or is one of the websites wrong?