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(Statics)Hammer and nail force and tension

  1. Sep 11, 2011 #1
    1. The problem statement, all variables and given/known data
    http://img4.imageshack.us/img4/1116/hammery.jpg [Broken]
    A block is placed under the head of the claw hammer to aid in removing the nail. Assuming that the hammer will not slip at point A...

    1) What is the tension in the nail rounded to the nearest newton
    2) The magnitude of the force exerted by the hammer at A rounded to the nearest Newton
    3) The direction of the force exterted by the hammer on the block at A rounded to the nearest degree.
    2. Relevant equations

    The three equilibrium equations
    Sum of x forces = 0
    Sum of y forces = 0

    3. The attempt at a solution

    I'm pretty sure the angle is irrelevant in 1 - It's simply finding the moments around A
    ΣMA = -200*0.211 + T*(0.05) = 0
    which got me an answer of 844N

    for part 2) trying to draw a free body diagram (including the downward force of the nail) but I'm not sure if I'm calculating anything quite correctly

    http://img854.imageshack.us/img854/1264/hammer2.jpg [Broken]

    ΣFx= (200*cos 24)*(0.211) + something = 0
    ΣFy = -844*0.05 + (200*sin24) ? = 0

    maybe? but probably not - I'm stabbing numbers in the dark. I know the answer should be around 44kN
    part 3) isn't the angle just the angle of the pull in the negative direction? (so -66 - I could be wrong, getting help in part 2 will help part 3 I'm sure.)

    Any help appreciated :shy:
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Sep 11, 2011 #2


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    1) is good. For 2), you should be summing forces in both directions, but you seem to be trying to sum moments in some cases.. The x and y components of all forces, including the unknown force components at A, must add to zero. For c)., the angle is correct, but you need to clarify the direction, and explain why.
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