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Homework Help: Youngs Modulus and angular speed.

  1. Nov 6, 2006 #1
    An amusement park ride consists of airplane-shaped cars attached to steel rods. Each rod has a length of 14.2 m and a cross-sectional area of 7.80 cm^2. Each car plus two people seated in it has a total weight of 1950 N.

    When operating, the ride has a maximum angular speed of 7.50 rev/min. How much is the rod stretched then?

    This problem does not give an angle or a radius of the circle, so I have two unknowns and cant get an answer.

    So far I have

    Tcos(theta) = mg

    Tsin(theta) =mv^2/r
  2. jcsd
  3. Nov 6, 2006 #2


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    Your unknowns are r and theta

    Are they related in anyway? (I'm assuming yes - they usually are, but I can't actually picture from your post whether I'm right. )
  4. Nov 6, 2006 #3
    r is the radius of the circle created as the masses on the rods swing in a circle.

    theta is the angle between the rod and its vertical support (perpendicular to the ground) as the masses swing outward

    EDIT: What you said got me to thinking and I got the answer now. Thanks
    Last edited: Nov 6, 2006