Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

geerky42

  • 2 years ago

Help Needed with Inertia...

  • This Question is Closed
  1. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    1 Attachment
  2. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ah... so the first thing you need to do is calculate the location of the centre of mass.. can you do that?

  3. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yeah, it's 1.95 m away from 1kg mass.

  4. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Not sure what to do in next step...

  5. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok.. i won't check that then.. fine.. now answer this.. if i know that there is a mass that is connected to a string.. which has a length 'l'.. and i swirled it.. what would be the moment of inertia???

  6. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1359715230549:dw|

  7. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \(\large I = \dfrac{1}{3}ml^2\), right?

  8. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    noooOOO :O.. how did you get that? :O

  9. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    its a point mass.. imagine its a point mass!!

  10. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Idk, it's a formula for end of rod, though this is what you asked for, sorry

  11. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    no.. what is the general formula for moment of inertia?? i think the concept itself is not clear to you.. huh?

  12. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    You mean \(\large I = ml^2\)?

  13. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    it's a general formula for inertia, i think.

  14. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    its \[\sum_{ }^{ } mR ^{2}\]

  15. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    thats the general formula.. and in my question .. since only one point mass is present.. you can say its just \[ml ^{2} \]

  16. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So for my question, I just use the sum of inertia?

  17. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so its basically summasation of all point mass times their distance from the axis of rotation squared.. so in your question.. you have 2 point masses.. so find each one's moment of inertia and sum it up

  18. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    and don't call it inertia.. its called moment of inertia :P

  19. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    inertia = resistance to change for linear motion moment of inertia = resistance to change for rotational motion

  20. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok I see. does this formula \(\displaystyle\int r^2 \text{d}m\) work too? I tired this way and I got lost.

  21. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    that is only if you have a rigid object.(continuos distribution of mass). but in your case its not a rigit object... its just 2 point masses.. !! so you can indivisually find their moment's of inertia about the rotational axis and sum them up..

  22. geerky42
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I see. Thanks!

  23. Mashy
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    your welcome :)

  24. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.