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Force from pendulum

  1. Jul 8, 2004 #1
    how do I calculate the force applied to a target using a pendulum of known weight, angle and lever arm?
  2. jcsd
  3. Jul 8, 2004 #2


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    A little more information would be nice. I take it you are lifting the pendulum to some specified angle and releasing it so that it strikes an object at the bottom?

    You can calculate its speed and momentum at the bottom by finding the potential energy when released: If the pendulum has length l and is raised an angle θ, then it potential energy is mgh= mgl(1- cos(θ)). At the bottom its potential energy is 0 so its kinetic energy is (1/2)mv2= mgl(1- cos(θ)) or v2= 2gl(1- cos(&theta)). Its momentum would be mv= m√(2gl(1- cos(&theta)).

    How much force that would hit something with depends upon exactly how the collision occurs. Does the pendulum come to a stop? How long does the collision continue?
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