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Homework Help: (Force Problems)

  1. Dec 7, 2005 #1
    Please Help! (Force Problems)

    Pulling horizontally on a rope moves a block with a total mass of 175.0 kg. If the coefficient of static friction between the block and the ground/slope is 0.12, what force must be applied to the rope to start the sled moving? If a second identical block is tied to the first block, and both are pulled with a force of 250.0 N, what acceleration will both experience, if the coefficient of kinetic friction is 0.10? Please help! I do not really understand how to approach this problem because I am having understanding forces.
     
  2. jcsd
  3. Dec 8, 2005 #2

    Chi Meson

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    Part one: what is the weight of your block?
     
  4. Dec 8, 2005 #3
    First part
    Limiting force will be static friction * N = static friction * mg
    that you can easliy calculate
    Second part
    Net force in the direction of motion will be
    250 -kinetic friction* (N1 + N2)
    = 250 -0.10(m1g + m2g)
    = (m1 + m2) a
    if you know m 1 and m2 ...you can easily calculate acceleration.

    enjoy
     
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