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Homework Help: 2 mass and veloc type physx problems

  1. Mar 8, 2010 #1
    Ive got two problems that are driving me crazy
    1. The problem statement, all variables and given/known data

    3. A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle. The coefficients of static and kinetic friction between the hockey puck and the metal ramp are μs = 0.40 and μk = 0.30, respectively. The puck's initial speed is 96 m/s. What vertical height does the puck reach above its starting point?


    4. The figure shows a 100 kg block being released from rest from a height of 1.0 m. It then takes 0.76 s to reach the floor. What is the mass of the block on the left?

    (attached pic)

    2. Relevant equations

    f=ma

    3. The attempt at a solution

    i dont really have an attempt just a bunch of notes and calculations but i dont know how to bring it together
    N=9.8*200sin(300) => 980n
    well im looking over it and dont have anything more than that i cant even tell what i was doing before. PLEASE help
     

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  2. jcsd
  3. Mar 8, 2010 #2
    Without an attempt, there's not much anyone can do to really help. I can tell you that for the second question, draw a free body diagram for each of the blocks, and since it is a taut string, the tensions T will be the same. Then use Fnet = ma, having found a using some basic 1 dimensional equations, and solve for m.
     
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