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Homework Help: Basic physics homework question

  1. Sep 10, 2007 #1
    1. The problem statement, all variables and given/known data

    Question #1:

    Δd=v¹Δt+½a(t)²

    Solve for: a

    Question #2:

    E= ½ m * v²
    Solve for: v



    2. Relevant equations

    Δd=v¹Δt+½a(t)²
    v = Δd / Δt
    a = v² - v¹ / Δt
    v² = v¹ + a * Δt
    Δd = (v² - v¹) * Δt
    Δd = v¹ * Δt + ½ a ( Δt )²
    E= ½ m * v²

    3. The attempt at a solution

    I'm not sure how to resolve this one.
     
  2. jcsd
  3. Sep 10, 2007 #2

    learningphysics

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    Homework Helper

    Just solve for a in the first equation... just like normal algebra... rearrange the equation etc...
     
  4. Sep 10, 2007 #3

    Astronuc

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    Staff Emeritus
    Science Advisor

    One needs to be consistent.

    This equation assumes constant acceleration, and t would be the elapsed time from application of the acceleration. v1 would normally the initial velocity (or speed) at the reference time, and d would be the distance at time t.

    See this - http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

    and

    http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html

    As learningphysics indicated, one can solve algebraically for the variables or coefficients in terms of variables and other coefficients.
     
    Last edited: Sep 10, 2007
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