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Homework Help: Horizontal force problem

  1. Feb 26, 2010 #1
    1. The problem statement, all variables and given/known data

    A 2.7 kg block initially at rest is pulled to the right along a horizontal, frictionless surface
    by a constant, horizontal force of 17.3 N. Find the speed of the block after it has
    moved 4 m. Answer in units of m/s.

    2. Relevant equations
    a=Fnet/mass


    3. The attempt at a solution
    17.3N/2.7Kg=6.40741m/s now what
     
  2. jcsd
  3. Feb 26, 2010 #2
    Re: force

    since the force is constant , this implies that the acceleration is constant as well .. so in this case you can use one of the kinematic equations ..

    vf = vo + a*t .. (vf=final velocity,vo=initial velocity,a=acceleration,t=time)
    vf^2 = vo^2 +2ax (x = distance of travel)
    x = vo*t + 0.5*a*t

    you have now a, in the question it is said that the block initially at rest(what that tells you about the initial velocity?), you have x , I think with these quantities you can find the final velocity(in other words, the velocity after the block has moved x=4m) ..
     
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