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Common forces in mechanics

  1. Jan 12, 2012 #1
    two blocks are connected by string if i pull a block,then block(it will transmit force) will also pull string then,string will also pull block (a& r pairs)forces on block are by me and by string of equal magnitude than why is block accelerating
  2. jcsd
  3. Jan 12, 2012 #2
    The force from the string on the block is not necessarily equal to your force on the block.
  4. Jan 12, 2012 #3


    Staff: Mentor

    common layman's usage is:

    I apply a force on a block and it moves.

    but for physics you need to think this way:

    I apply a force (f=ma) on a block of mass m and it accelerates (no friction case).

    in the real world with friction:

    I apply a force (f=ma) on a block of mass m and it accelerates to some constant
    speed because the frictional force increases with increasing speed and opposes the
    force Im applying.
  5. Jan 12, 2012 #4

    i am not getting it
  6. Jan 12, 2012 #5
    why? it because,the block may not transferring all force i am applying.
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