# Statics problem. Is my work correct?

• Blugga
In summary, the conversation discusses a problem involving statics and the correct method for identifying external forces and setting up a free body diagram. The conversation also mentions the importance of including all internal forces, such as the tension in a cable, when analyzing the system. Finally, the conversation concludes with the solution to the problem and a note of gratitude for the assistance provided.
Blugga

ƩF=0
ƩM=0

## The Attempt at a Solution

I have done parts 1-3 (parts 1-2 in image) and I think it's right. It's been a while since I've had statics and I'm not 100% sure it's right. For part 4, where the pulley meets the frame at F do I need a Fx and Fy? or Fx ,Fy, and MF?

Your initial FBD of the system (the whole frame) is not correct. You seem to have cut the rope and identified the internal horizontal cable tension as 500 N to the right at C, but you left off the internal horizontal cable tension of 500 N that acts to the left at the top of the pulley.
Don't cut the rope yet, and focus instead on the whole system and identify the external forces acting on it. The external forces are the applied vertical load of 500 N down on the rope, and the reaction forces at A and E. The horizontal cable tension is internal to the system and thus is not an external force, so it does not come into play when looking at the FBD of the system. Now sum moments and forces equal to 0. You will find perhaps a surprising result for the reaction at E.

PhanthomJay said:
Your initial FBD of the system (the whole frame) is not correct. You seem to have cut the rope and identified the internal horizontal cable tension as 500 N to the right at C, but you left off the internal horizontal cable tension of 500 N that acts to the left at the top of the pulley.
Don't cut the rope yet, and focus instead on the whole system and identify the external forces acting on it. The external forces are the applied vertical load of 500 N down on the rope, and the reaction forces at A and E. The horizontal cable tension is internal to the system and thus is not an external force, so it does not come into play when looking at the FBD of the system. Now sum moments and forces equal to 0. You will find perhaps a surprising result for the reaction at E.

Yes, I did figure it out. I left out the force to the left on top of the pulley. That gave me new answers. Ex turned out to equal 0.

Thanks for the help.

## 1. What is the purpose of statics in science?

Statics is a branch of mechanics that deals with the study of objects at rest or in constant motion. It helps scientists understand and predict the behavior of structures and systems under various forces and loads.

## 2. How do I know if my statics problem is correct?

To determine the correctness of a statics problem, you can follow a step-by-step approach and check if all the equations and calculations are accurate. Additionally, you can also compare your solution with the answer provided in the problem or consult with a fellow scientist or instructor.

## 3. What are the common mistakes in solving statics problems?

Some common mistakes in solving statics problems include using incorrect equations, not considering all the forces acting on an object, and not properly labeling and organizing the given information. It is important to double-check your work and be mindful of these potential errors.

## 4. How can I improve my understanding of statics?

To improve your understanding of statics, it is important to have a strong foundation in mathematics and physics. Additionally, practicing and solving various statics problems can help you become more familiar with different concepts and techniques.

## 5. Are there any online resources for learning and practicing statics?

Yes, there are many online resources available for learning and practicing statics, such as tutorial websites, video lectures, and interactive problem-solving tools. You can also find practice problems and quizzes on various educational websites and forums.

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