Solving Simple Forces Problem | FE Exam Prep | Mental Block

  • Thread starter nikkelm
  • Start date
  • Tags
    Forces
In summary, the conversation discusses a problem involving a circular rod subjected to several forces and determining the displacement relative to C. The diameter, length, and material properties of the rod are given. The conversation also addresses a potential error in the problem and suggests using d'Alembert's principle to solve it.
  • #1
nikkelm
4
0
I am studying for the FE exam and came to this problem:

A circular rod of 1in. cross-section area is subjected to several forces. Determine the displacement relative to C (in the attachment). Assume E =29x10^6 psi.

my solution is:

del=1/29x10^6(Fa-b(10in)/1in+Fc-b(8in)/1in)

yet I don't know how to get the right forces Fa-b and Fc-b

signed,

Mental Block
 
Physics news on Phys.org
  • #2
Welcome to PF!

nikkelm said:
A circular rod of 1in. cross-section area is subjected to several forces. Determine the displacement relative to C (in the attachment) …

Hi nikkelm! Welcome to PF! :smile:

erm … no attachment … ! :cry:

Actually, it takes ages to get an attachment approved.

It'll be much quicker if you just describe the picture to us in words! :smile:
 
  • #3
Oh... I guess that's for copy right infringement stuff... anyways, the cylinder axis is oriented horizontally and it is 18 in long from A to C and 10 inches long from A to B. A is at the left C at the far right with B in the middle, of course. The force at A is 2kip to the left. The force at B is 4kip to the right. The force at C is 4kip to the left again.
 
  • #4
Before you go too far, I think you mean the force at C is 2K to the left, or else you're not in equilibrium.
 
  • #5
nikkelm: Once you resolve the equilibrium issue, you could perform a section cut anywhere you wish, then solve for the unknown force acting on your free-body diagram, to obtain the force in each segment.
 
  • #6
That explains things.. there is an error in the problem because it definitely shows a 4kip force
 
  • #7
Is there any support on the rod? We would need to know about any support(s) on the rod, since we can't see your diagram. If it has no supports, then the rod is accelerating to the left. If accelerating, you might be able to use d'Alembert's principle to obtain the force on any section cut.
 
  • #8
no, it isn't a kinematics question I am pretty sure it is a mistake. it is a multiple choice and the forces are supposed to be 2kip ea. which makes sense if they meant for it to be 2kip to the left at C.
 

1. What is the best approach to solving simple forces problems on the FE exam?

The best approach to solving simple forces problems on the FE exam is to first understand the fundamental principles of forces, such as Newton's laws and the concept of equilibrium. Then, break down the problem into smaller parts and use the appropriate equations and diagrams to solve for the unknown variables.

2. How can I overcome mental blocks when trying to solve simple forces problems?

One way to overcome mental blocks when solving simple forces problems is to practice regularly. Familiarize yourself with different types of problems and their solutions. Also, take breaks and don't get too stuck on one problem. Sometimes a fresh perspective can help clear the mental block.

3. Are there any common mistakes to avoid when solving simple forces problems?

Yes, some common mistakes to avoid when solving simple forces problems include not drawing accurate diagrams, not considering all the forces acting on an object, and not using the correct equations or units. It is important to double-check your work and make sure all the steps are logical and consistent.

4. How can I improve my problem-solving skills for simple forces on the FE exam?

To improve your problem-solving skills for simple forces on the FE exam, it is important to practice regularly and familiarize yourself with different types of problems. Understanding the underlying principles and concepts is also crucial. Additionally, it can be helpful to work through problems with a study group or seek guidance from a mentor or tutor.

5. Can I use a calculator to solve simple forces problems on the FE exam?

Yes, you are allowed to use a calculator on the FE exam to solve simple forces problems. However, it is important to be familiar with the calculator's functions and know how to use it efficiently. It is recommended to practice using the calculator beforehand to avoid any confusion or errors on the exam.

Similar threads

Statics 2D Virtual Work problem regarding calculation of Normal force
    • Engineering and Comp Sci Homework Help
Replies
4
Views
4K
Solving Beam Theory & Statics Problems with Difficulties
    • Engineering and Comp Sci Homework Help
Replies
11
Views
3K
Curiosity Question 1: Compression force from tension
    • Introductory Physics Homework Help
Replies
11
Views
2K
Change in length LSolve Engineering Problems: P, Brass, Steel
    • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
Solving a Steel Rod Temperature Expansion Problem
    • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
Solving 2 Simple Force Problems: Understanding Force Magnitude and Application
    • Introductory Physics Homework Help
Replies
2
Views
27K
How Can I Solve These Vectors and Kinematics Exam Problems?
    • Introductory Physics Homework Help
Replies
2
Views
2K
Solving Textbook Problems for Exam Prep: Angular Momentum & Impulse
    • Introductory Physics Homework Help
Replies
2
Views
4K
How Do You Solve Basic Physics Problems Involving Friction, Force, and Motion?
    • Introductory Physics Homework Help
Replies
2
Views
2K
BRS: Random Comments on Some Recent PF Threads
    • Special and General Relativity
3
Replies
94
Views
8K

Hot Threads

Recent Insights

Back
Top