Trouble with elasticity and torque on a body in equilibrium

In summary, the conversation discusses the forces and torques acting on a U-shaped metal bar that is stuck in the ground and being widened by a force applied on the right side. While there may be 2 forces on the horizontal direction, there will be a resultant torque no matter which point is taken as the origin, causing the bar to not be in equilibrium. The solution may lie in considering the entire length of the bar in the ground instead of just a single point. A diagram may help clarify the situation.
  • #1
FG_313
17
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?
 
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  • #2
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
 
  • #3
+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.
 

1. What is elasticity?

Elasticity is the ability of a material to deform when a force is applied and then return to its original shape when the force is removed.

2. How does elasticity affect equilibrium?

Elasticity can affect equilibrium by causing a body to change its shape or size in response to external forces. This can result in a shift in the center of mass and a change in the distribution of forces, which can disrupt equilibrium.

3. How do you calculate torque on a body in equilibrium?

Torque is calculated by multiplying the force applied to an object by the distance from the pivot point to the point where the force is applied. The direction of the torque is determined by the direction of the force and the direction of rotation.

4. What factors can affect the elasticity of a material?

The elasticity of a material can be affected by factors such as temperature, pressure, and the material's composition and structure. For example, increasing temperature can cause a material to become more elastic, while increasing pressure can make a material less elastic.

5. How can you maintain equilibrium when dealing with elasticity and torque?

To maintain equilibrium when dealing with elasticity and torque, it is important to carefully consider the forces acting on the object and their distribution. Additionally, choosing materials with appropriate elasticity and considering any external factors that may affect the object's equilibrium, such as temperature or pressure, can help maintain balance.

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