Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Calculating the Dieing Time of a Pendulum

  1. Apr 4, 2005 #1
    Hi everybody,

    I need to calculate a pendulums dieing time(I don't know actually what the correct word in English is for that. It is the time between the starting of swinging and the end of swinging). The ball of pendulum is 15kg made of lead and the wire is 15m. I have only these values. How can I calculate this? If I need some coefficients, where can I find them?


    (I hope that I opened this topic in right zone. And sorry for my bad English.)
  2. jcsd
  3. Apr 4, 2005 #2


    User Avatar
    Science Advisor

    You need a friction coefficient. With no friction, the pendulum will never "die".
    There is no way you can look that up- it is different for every pendulum.

    (And your English is excellent. Far better than my (put almost any language here).)
  4. Apr 4, 2005 #3


    User Avatar
    Science Advisor

    Well, this is crazy enough it just might work. You know lead has a certain density, and you know the mass. Based on this, you can find the volume. Based on the shape of a sphere, the mass, and the size, one could calculate the air resistance with an assumed air density (just assume room temp.). That is, if you can calculate the velocity of the pendulum swinging.

    I'm thinking it would involve some guessing, or some crazy integration. Perhaps you could set something up in Excel to do some iterations or something like that...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook