1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B Tuned mass dampers in Taipei 101

  1. Jan 13, 2017 #1
    When I was in lesson today, our physics teacher mentioned a device called tuned mass dampers in Taipei 101 to reduced the effect of earthquakes. What he said is that when the building shifts to the right, and there will be a mechanism for the big ball (the damper) to shift to the left to counteract, and vice versa. The question I have is that wouldn't the shift of the damper be an internal force, so how does that changed anything resulted by the earthquakes waves, an external force. I mean the movement of the damper should not shift the centre of mass if the whole thing. Thanks in advance.
    Last edited: Jan 13, 2017
  2. jcsd
  3. Jan 13, 2017 #2


    User Avatar

    Staff: Mentor

    A heavy mass up near the top so that when the base is shaken the building doesn't sway as much as it otherwise would. I don't know specifically about tuning, just that you would need to be mindful of its natural resonances.
  4. Jan 13, 2017 #3


    User Avatar
    Science Advisor

    Of course it does, but that isn't the point. Rather the delay and thus movement in counter phase to dampen the oscillation.
  5. Jan 13, 2017 #4
    why would the centre of mass of the damper+the building change if we just move the damper, aren't they the internal force of the same system
  6. Jan 16, 2017 #5


    User Avatar
    Science Advisor

    If only the damper moves, then the centre of mass of damper+building also moves. But that isn't even what is happening or the point of the system.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted