Trouble with elasticity and torque on a body in equilibrium

Click For Summary
SUMMARY

The discussion centers on the analysis of forces and torques acting on a U-shaped metal bar in equilibrium when a force is applied to its top. Participants emphasize the importance of considering all forces, including the elastic force from the bar and the torque generated by the forces acting on the bar's base. A key conclusion is that the base of the bar cannot be treated as a single point due to its length, which affects torque calculations. Diagrams are recommended for better visualization of the forces and torques involved.

PREREQUISITES
  • Understanding of basic mechanics, specifically forces and torques
  • Familiarity with equilibrium conditions in static systems
  • Knowledge of elastic deformation in materials
  • Ability to create and interpret diagrams representing physical systems
NEXT STEPS
  • Study the principles of static equilibrium in mechanics
  • Learn about elastic deformation and stress-strain relationships in materials
  • Explore torque calculations and their applications in engineering
  • Practice creating diagrams to visualize forces and torques in mechanical systems
USEFUL FOR

Mechanical engineers, physics students, and anyone involved in analyzing static systems and understanding the principles of forces and torques in equilibrium.

FG_313
Messages
17
Reaction score
1
Supose we have a ¨U-shaped" metal bar, stuck in the ground, and I aply a force on the top of the part on the right, trying to make it wider. If I were to avaliate the forces acting on a specific part of the bar that includes the point that I´m applying the force, let`s say the portion from that point to half the height of the U-shaped bar, there would be 2 forces on the horizontal direction (ignoring the weight): my force and an elastic force from the metal bar (It will deform a little bit until it matches my force). But, if I were to avaliate Torques acting on that portion of the U-bar, and If I took the reference point on any of the points which the one of the two forces are acting, there would be a resultant torque, which is impossible, since it`s in equilibrium. Where have I got this wrong? And why?
 
Physics news on Phys.org
I think you need a diagram. I'm not sure I understand your problem.

If you have no special software, you could use a simple Paint program and attach a .png file to your post.

avaliate - I think you mean evaluate

I think you are not considering all possible forces. I've quickly added more on a diagram,( though I can't say they are accurate or complete.)
Ubolt.png
 
+1 about a diagram.

I believe the answer is that the part in the ground is not a single "point" that you can take as the origin. Rather there is a "length" of pipe in the ground. What ever point you choose as origin there will be a force acting on the bit in the ground to provide a torque.

This is true even if the bit in the ground is curved like the bottom of the letter u.
 

Similar threads

Undergrad Confusion About Rotational Motion
  • · Replies 19 ·
Replies
19
Views
2K
Engineering Equilibrium equations of elastic body
  • · Replies 31 ·
2
Replies
31
Views
4K
Undergrad A rotating system of two point particles with inner torque
  • · Replies 1 ·
Replies
1
Views
1K
Graduate Extension of an elastic block of Neo-Hookean material
  • · Replies 10 ·
Replies
10
Views
1K
Graduate Who Can Solve the Mystery of the True Torque?
  • · Replies 16 ·
Replies
16
Views
2K
Torque: find the force necessary for a body to be in equilibrium
  • · Replies 6 ·
Replies
6
Views
2K
Equilibrium of Forces and Torques on Sawhorses Supporting a Person on a Board
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Torque and rigid body rotation
  • · Replies 5 ·
Replies
5
Views
5K
Graduate Oscillation of a boat in still water (Metacenter and Center of Mass)
  • · Replies 24 ·
Replies
24
Views
2K
Graduate What is the definition and significance of torque in physics?
  • · Replies 1 ·
Replies
1
Views
4K