phy1020.DVI

8.7 Other Pendulums

• Double pendulum.Adouble pendulumis formed by attaching one pendulum to the bob of another, so
  that the two pendulums are attached vertically and both bobs are free to move. The motion of a double
  pendulum is a classic exercise in an advanced formulation of Newtononian classical mechanics called
  Langrangian mechanics.


• Ballistic pendulum.Aballistic pendulumis a type of pendulum used to measure the speed of high-
  speed objects like bullets. A bullet is fired into the pendulum bob, and the pendulum is constructed
  with a ratchet mechanism that holds the pendulum in place once it reaches its maximum displacement
  from the vertical. Knowing the masses of the bullet and pendulum bob, the length of the pendulum,
  and the angle the pendulum reaches when the bullet is fired into it, it is possible to deduce the velocity
  of the bullet.


• Foucault pendulum.AFoucault pendulumis a type of simple plane pendulum that is used to demon-
  strate the rotation of the Earth. As the pendulum swings back and forth in a plane, the Earth rotates
  underneath the pendulum, causing its trace along the ground to drift with time.