• Support PF! Buy your school textbooks, materials and every day products Here!

Friction and inclines problem. i need help

  • Thread starter Terrell
  • Start date
  • #1
317
25
[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
 

Attachments

Last edited by a moderator:

Answers and Replies

  • #2
PeroK
Science Advisor
Homework Helper
Insights Author
Gold Member
12,338
5,138
You need a better free body diagram, showing the forces at the top and bottom of the ladder.
 
  • #3
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
317
25
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
Science Advisor
Homework Helper
Insights Author
Gold Member
32,730
5,030
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.
 

Related Threads on Friction and inclines problem. i need help

  • Last Post
Replies
2
Views
9K
Replies
1
Views
2K
Replies
3
Views
8K
  • Last Post
Replies
18
Views
5K
Replies
1
Views
1K
Replies
7
Views
615
  • Last Post
Replies
23
Views
15K
Replies
1
Views
11K
Top