- #1
clarineterr
- 14
- 0
Homework Statement
A window washer of mass M is sitting on a platform suspended by a system of cables and pulleys as shown . He is pulling on the cable with a force of magnitude F. The cables and pulleys are ideal (massless and frictionless), and the platform has negligible mass.Find the magnitude of the minimum force F that allows the window washer to move upward.
Express your answer in terms of the mass M and the magnitude of the acceleration due to gravity g.
Homework Equations
Newton's second Law
The Attempt at a Solution
For the person: Ma = F + T -Mg where T is the tension in the cable holding the platform and F is the force of the rope on the washer.
Then from the lower washer T = 2T[tex]_{1}[/tex], where T[tex]_{1}[/tex] is the tension in the rope
So Ma = F + 2T[tex]_{1}[/tex] - Mg
The block is about to move so Ma = 0 and I think T[tex]_{1}[/tex]=F so then
0 = 3F - Mg
I am not sure about this though