Friction and inclines problem. i need help

  • Thread starter Terrell
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  • #1
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[moderator note: moved from technical forums, no template]

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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  • #2
PeroK
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You need a better free body diagram, showing the forces at the top and bottom of the ladder.
 
  • #3
wrobel
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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.
 
  • #5
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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.
can i solve this without torques? i haven't got into torques just yet
 
  • #6
haruspex
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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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