Equation for sum of torques on a ladder and minimum angle

AI Thread Summary
The discussion focuses on calculating the sum of torques for a ladder in equilibrium. It emphasizes the importance of accurately identifying all forces and torques, particularly noting that three torques must be considered when calculating about the point of contact with the ground. The torque generated by the force at the wall, labeled as F_{f2}, is highlighted as a crucial component often overlooked. Properly accounting for all torques is essential for solving the problem correctly. Understanding these principles is vital for mastering torque calculations in physics.
Howard Fox
Messages
38
Reaction score
2

Homework Statement


upload_2018-12-3_17-6-53.png
[/B]
upload_2018-12-3_17-10-32.png

upload_2018-12-3_17-13-19.png

Homework Equations


Drawing a diagram for the forces is the easy part. I am not sure I am doing the equation of the sum of the torques well.

The Attempt at a Solution


This is my attempt for the forces[/B]
upload_2018-12-3_17-35-22.png

And this for the torques:
upload_2018-12-3_17-57-34.png
 

Attachments

  • upload_2018-12-3_17-6-53.png
    upload_2018-12-3_17-6-53.png
    29.1 KB · Views: 591
  • upload_2018-12-3_17-10-32.png
    upload_2018-12-3_17-10-32.png
    11.3 KB · Views: 621
  • upload_2018-12-3_17-13-19.png
    upload_2018-12-3_17-13-19.png
    6.6 KB · Views: 574
  • upload_2018-12-3_17-35-22.png
    upload_2018-12-3_17-35-22.png
    10.6 KB · Views: 591
  • upload_2018-12-3_17-57-34.png
    upload_2018-12-3_17-57-34.png
    16.9 KB · Views: 544
Physics news on Phys.org
If you calculate torques about the point of contact with the ground, there are 3 torques to consider not just 2. You missed the torque generated by ##F_{f2}## at the point of contact with the wall.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Force of the Ladder on a Wall Torque
Replies
5
Views
3K
A hanging ring carrying current in a uniform magnetic field
Replies
10
Views
315
Net Torque Within a Mass and Pulley System
Replies
22
Views
2K
Frequency & Wavelength of a Vibrating Wire
Replies
5
Views
1K
Does distance affect torque in hanging sign problem?
Replies
42
Views
4K
Derivation Of Torque On Current Loop Due To Uniform Magnetic Field
Replies
4
Views
1K
Torque on a sign hung by a hinge
Replies
3
Views
583
Torque on a Circular Current Loop under a Misaligned Magnetic Field
Replies
1
Views
939
Why Isn't the Sum of Torques Zero in This Ladder Equilibrium Problem?
Replies
8
Views
6K
How Do You Calculate the Angle of a Slipping Ladder?
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top