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Homework Help: Velocity/displacement 11th grade physics

  1. Feb 13, 2008 #1
    1. The problem statement, all variables and given/known data
    A truck that is skidding out of control has its initial velocity halved. How will this effect the total displacement of the skidding truck, vs the amount of displacement if the truck were at its original velocity

    2. Relevant equations
    displacement= Vi(t)+1/2AT^2 Vi=initial velocity.... A=acceleration...T=time

    3. The attempt at a solution
    I believe that the result would be around less than half the displacement. My reasoning is that the total time to stop would be less, because there is less of a velocity, and also that since the velocity is lower, that the truck would be covering less distance throughout the whole time..... maybe 1/3 or around that as a ballpark guess.
  2. jcsd
  3. Feb 14, 2008 #2
    Try putting some variables in the displacement function, for example Vi = a m/s, A = a/4 m/s^2. Now put Vi = 2a. Compare the expressions then.
  4. Feb 14, 2008 #3
    dear frnd... kbaumen never encourage your colleagues to put values and solve questions...

    trial and error methods are very uncivilized and baseless methods..

    they may solve a problem for you but they shall cease to help ya in the long run....

    use maths to help ya always.....


    s1=1/2 v/t *t^2
    s2=1/2 v/2t *t^2


    assumptions=the truck starts from rest ..the acceleration is constant.. and the displacements are measured in the same time interval.
  5. Feb 17, 2008 #4
    Thanks for the advice.
  6. Dec 31, 2008 #5
    The formula for displacement that you used is the same formula i use for solving for distance? why is that? this is to lax113
  7. Dec 31, 2008 #6
    displacement is distance, but it takes into account direction, whereas distance doesn't...so its the same formula for both
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