Friction and inclines problem. i

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Homework Help Overview

The discussion revolves around a problem involving friction and inclines, specifically related to a ladder's equilibrium. Participants are exploring the forces acting on the ladder and the application of torques in solving the problem.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need for a better free body diagram to visualize the forces involved. There are references to theorems regarding the equilibrium of rigid bodies and the necessity of considering torques. Some participants question whether the problem can be solved without using torques, given the number of unknowns involved.

Discussion Status

The discussion is active, with participants providing guidance on the importance of free body diagrams and theorems related to equilibrium. There is a recognition that multiple approaches are being considered, particularly regarding the use of torques in the solution.

Contextual Notes

Participants note that the problem is constrained by the requirement to balance forces and torques, with the original poster expressing uncertainty about the application of torques in their current understanding.

Terrell
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this is fun but i am stuck. help! :) the first image states the problem and the second image is my futile attempt at a solution
 

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You need a better free body diagram, showing the forces at the top and bottom of the ladder.
 
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Theorem. If a rigid body is in rest then the sum of torques about any point is equal zero and the sum of forces is also equal zero.
It is convenient to calculate torques about one of two contact points of the ladder and the wall/floor.
 
wrobel said:
Theorem. If a rigid body is in rest then the sum of torques about any point is equal zero and the sum of forces is also equal zero.
It is convenient to calculate torques about one of two contact points of the ladder and the wall/floor.
can i solve this without torques? i haven't got into torques just yet
 
Terrell said:
can i solve this without torques? i haven't got into torques just yet
No. You have three unknowns, the two normal forces and the angle. So you need three equations. Only two are available from linear force balances in two dimensions, so your third must be from torque balance.
 
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