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Please help if possible with these dynamics problems

  1. Sep 29, 2005 #1
    I'm struggling with these problems from my dynamics class. Any help is GREATLY appreciated. Thanks for even looking.

    1.The winding drum D is drawing in the cable at an accelerated rate of 5 m/s^2. Determine the cable tension if the syspended crate has a mass of 800 kg.


    2. The ball has a mass of 30 kg and a speed of v=4m/s at the instant it is at its lowest point theta= 0 degrees. Determine the tension in the cord and the rate at which the ball's speed is decreasing at the instant theta= 20 degrees. Neglect the size of the ball.

    picture 2:

    3. For a short time, the 250 kg roller coaster is traveling along the spiral track such that its posistion measured from the top of the track has components r= 8m, theta= (0.1t + 0.5) rad, and z= (-0.2t) m, where t is in seconds. Determine the magnitude of the components of force which the track exerts on the car in the r, theta, and z directions at the instant t=2s. Neglect the size of the car.


    4. The spool, which has a mass of 2 kg, slides along the smooth horizontal spiral rod, r= 0.4theta m, where theta is in radians. If its angular rate of rotation is constant and equals to theta-dot = 6 rad/s, determine the horizontal tangential force P needed to cause the motion and the horizontal normal force component that the spool exerts on the rod at the instant theta= 45 degrees.

    pic 4:
    Last edited: Sep 29, 2005
  2. jcsd
  3. Oct 2, 2005 #2


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    I think you'll get more replies if you explain what you've tried and where you are stuck.
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