M2 Point C Moment Calculation: Why is it Not the Same as Book?

In summary, the conversation discusses solving a problem involving moments at points C and D. The person is confused about why their answer does not match the answer given in the book when using moment about D. They discuss the direction of the force at point D and the displacement vector. Finally, they correct their previous mistake and confirm that when taking moments about D, the correct answer is 22.5j+30k.
  • #1
werson tan
183
1

Homework Statement


for M2 , if i take the moment at pont C , then my ans would be (0.3i) x ((125X(3/5) j +125(4/5) k )= 30j +22.5k
Which is not same with the book which use moment about D . why ? Is the value at the triangle at te upper part incorrect (circle part) ?

Homework Equations

The Attempt at a Solution

 

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  • #2
Picture is too small to read.
 
  • #3
paisiello2 said:
Picture is too small to read.
 

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  • #4
Still too small. Just blow up the diagram.
 
  • #5
If you are taking moments about C then presumably you are considering the force at D. Isn't that in the direction -3/5j+4/5k? And should't the displacement vector be -3i?
 
  • #6
haruspex said:
If you are taking moments about C then presumably you are considering the force at D. Isn't that in the direction -3/5j+4/5k? And should't the displacement vector be -3i?
Ya, I would ended up getting 22.5k +30j . But if I take moment about D , I would get 22.5j+30k... Is it correct?
 
  • #7
werson tan said:
Ya, I would ended up getting 22.5k +30j . But if I take moment about D , I would get 22.5j+30k... Is it correct?
No, sorry, I had it wrong. The force at D is in the direction -4/5j+3/5k.
 

Related to M2 Point C Moment Calculation: Why is it Not the Same as Book?

1. What is M2 Point C Moment Calculation?

M2 Point C Moment Calculation is a method used to calculate the moment of inertia of a body or object with respect to a specific point, typically the center of mass. It takes into account the mass and distribution of the object to determine its resistance to rotational motion.

2. How is M2 Point C Moment Calculation different from other methods?

M2 Point C Moment Calculation differs from other methods, such as M1 Point A Moment Calculation, by using a different reference point. M1 Point A Moment Calculation uses the point of support or pivot point as the reference point, while M2 Point C Moment Calculation uses the center of mass as the reference point.

3. Why is M2 Point C Moment Calculation not the same as the book?

The M2 Point C Moment Calculation may not be the same as what is stated in a book due to a variety of factors. These can include differences in the object's shape, mass distribution, and measurement accuracy. It is important to use the correct formula and data for accurate calculations.

4. What are some common applications of M2 Point C Moment Calculation?

M2 Point C Moment Calculation is commonly used in engineering and physics to analyze the stability and balance of structures, such as bridges and buildings. It is also used in the design of machines and tools to ensure proper functionality and safety.

5. How can I ensure accurate M2 Point C Moment Calculation?

To ensure accurate M2 Point C Moment Calculation, it is important to use precise and accurate measurements of the object's mass and distribution. It is also crucial to use the correct formula for the specific object and reference point. Double-checking calculations and consulting with experts can also help to ensure accuracy.

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