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experimentX Group Title

Q.

  • 2 years ago
  • 2 years ago

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  1. experimentX Group Title
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    |dw:1350734665748:dw|

    • 2 years ago
  2. Callisto Group Title
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    Third case: T = g?

    • 2 years ago
  3. experimentX Group Title
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    well ... its g N

    • 2 years ago
  4. experimentX Group Title
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    first case??

    • 2 years ago
  5. Callisto Group Title
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    Wait. N = unit?

    • 2 years ago
  6. experimentX Group Title
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    yes ... tension always has unit of force ... except for surface tension.

    • 2 years ago
  7. Callisto Group Title
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    First case: Σ F = mg mg - T = mg T = 0

    • 2 years ago
  8. Callisto Group Title
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    Second case: Σ F = ma mg - T = ma T = m (g-a) = m(g-5) Unit: N for first and second case.

    • 2 years ago
  9. Callisto Group Title
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    But..... but.... but.... the reel.... Shouldn't I take it into consideration??

    • 2 years ago
  10. experimentX Group Title
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    you get acceleration after considering the rotational motion of reel. it shouldn't make any difference.

    • 2 years ago
  11. experimentX Group Title
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    in other words you have already taken care of rotational motion of reel. still if you need to verity then ... T*R = torque being applied on reel.

    • 2 years ago
  12. experimentX Group Title
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    sorry .. mg*R - TR = torque being applied on reel ... that makes it go round.

    • 2 years ago
  13. experimentX Group Title
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    mg*R - TR <--- this part creates motion.

    • 2 years ago
  14. Callisto Group Title
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    acc. of the reel = acc. of the mass?

    • 2 years ago
  15. experimentX Group Title
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    no ... the reel does not have linear acceleration. It's rotating ... it has angular acceleration.

    • 2 years ago
  16. Callisto Group Title
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    tangential acc. of the reel = acc. of teh mass?

    • 2 years ago
  17. experimentX Group Title
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    yes ... maybe ... worth checking it out.

    • 2 years ago
  18. Callisto Group Title
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    If we don't have the acc. of the reel, how can we suppose to find torque, so that we can find tension!?

    • 2 years ago
  19. experimentX Group Title
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    well .. we have to find the acceleration reel first.

    • 2 years ago
  20. experimentX Group Title
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    or acceleration of the mass falling down first.

    • 2 years ago
  21. Callisto Group Title
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    But.. how...

    • 2 years ago
  22. experimentX Group Title
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    using conservation of energy \[ {1 \over 2} mv^2 + {1 \over 2}I \omega^2 = mgh \\ \omega r = v,\] solving those two will give you final velocity, you know distance 'd', and initial velocity.

    • 2 years ago
  23. experimentX Group Title
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    solve for acceleration of the using it.

    • 2 years ago
  24. Callisto Group Title
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    Wow! We're doing it backward!

    • 2 years ago
  25. Callisto Group Title
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    (c) -> (b) -> (a) :O

    • 2 years ago
  26. experimentX Group Title
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    well ...

    • 2 years ago
  27. Callisto Group Title
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    That's not a problem :P

    • 2 years ago
  28. experimentX Group Title
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    the other way ... "tangential acc. of the reel = acc. of teh mass" ... at the circumference of reel ... they go foot to foot.

    • 2 years ago
  29. Callisto Group Title
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    Yes. Then we can find the angular acc. Using integration to find the moment of inertia, and then use it to find the torque. Is it possible?

    • 2 years ago
  30. experimentX Group Title
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    yep .. this is also possible.

    • 2 years ago
  31. Callisto Group Title
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    For the energy one, can we really use that way?

    • 2 years ago
  32. experimentX Group Title
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    sure ... the torque will always be constant ... hence there will be constant acceleration.

    • 2 years ago
  33. Callisto Group Title
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    I'm sorry, but how do I know if the torque is constant?

    • 2 years ago
  34. experimentX Group Title
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    the torque depends on two parameters \( r \times F\) , F is part of mgh while r is radius of wheel. both are not changing ... neither is their angle between them.

    • 2 years ago
  35. Callisto Group Title
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    mgh?! the PE of the reel or..?!

    • 2 years ago
  36. Callisto Group Title
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    hmm?

    • 2 years ago
  37. experimentX Group Title
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    mass .. hold on ... there seems to be discrepancy with second method.

    • 2 years ago
  38. experimentX Group Title
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    |dw:1350737767080:dw|

    • 2 years ago
  39. experimentX Group Title
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    |dw:1350737955528:dw|

    • 2 years ago
  40. Callisto Group Title
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    Hmm.. So, you're just considering the mass m ..?

    • 2 years ago
  41. experimentX Group Title
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    |dw:1350738106593:dw|

    • 2 years ago
  42. Callisto Group Title
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    |dw:1350738529141:dw|

    • 2 years ago