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Homework Help: Simple Pendulum HELP!

  1. Feb 4, 2009 #1
    1. The problem statement, all variables and given/known data
    A pendulm bob weighing 0.1 kg hangs from a light tread. it has a length of 25 cm and a period is 1 second and the force is 1.1 N. what is the maximum velocity of the pendulum bob?

    2. Relevant equations
    F = M * A
    V = U + A*T

    3. The attempt at a solution
    Using these formulas i got the final velocity, but it does not seem right!
  2. jcsd
  3. Feb 4, 2009 #2
    Acceleration isn't constant so you can't use F=ma, or v = u + at
    When is the velocity at a maximum do you think?
  4. Feb 4, 2009 #3
    Do you have access to internet? Typing in "simple pendulum" will enable you to find these formulae.

    Period = 2*PI*SQRT(Length/g)
    You shouldn't need this one but beware of units if you use it.

    RestoringForce= -Mass*g*sin(theta)
    This can get us the maximum angle, and thus the maximum height of the bob, and thus the potential energy, and thus the kinetic energy and thus the maximum velocity.
  5. Feb 4, 2009 #4
    The maximum velocity is at the equlibrium point. i.e when the pendulum is pointing down.
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