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Problems with Newton's Second Law

  1. Feb 11, 2009 #1
    1. The problem statement, all variables and given/known data

    Given a car being pushed by a constant force:

    a. How will the acceleration change in relation to the mass of the car? --> Done, it'll decrease
    b. How will a graph of acceleration in the y axis and and (1/m) being the x axis will look like? What will the slope of the graph mean? --> Trouble with this one

    2. Relevant equations

    F = ma
    a = F(1/M)

    3. The attempt at a solution

    For part B, I have already determined the graph should be decreasing, but I have doubts if it's exponential or as (1/x) does. I think it's as (1/x), since F is constant. As to what the slope means, I think it refers to the Inertia of the object in question. I have serious doubts with this though.

    Any help is greatly appreciated.
  2. jcsd
  3. Feb 11, 2009 #2


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    Homework Helper

    I don't care for this answer, which is an oversimplification! In my opinion, the question asks for a "relationship" between mass and acceleration. That word "relationship" means they want the formula relating mass and acceleration. You probably have a formula with an "m" and an "a" in it. The thing to do is rearrange it so it says "a = ...".

    For the b part, compare your formula for a= with the some standard formulas.
    For example, y = slope*x + b is the formula for a straight line.
    y = a*x^2 is a quadratic or parabola
    y = a*e^x is an exponential.
    Which one fits your formula for "a=" . . . with the "y" replaced by "a", the "x" replaced by "1/m" ?
    You should find that it is one of the above, exactly, so you will know whether the graph is linear, parabolic or exponential.
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