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Distance Travelled Over Time

  1. Nov 16, 2005 #1
    Hi, all

    I have a question that I've been Googling for the past hour or so, and cannot find the answer to. I seem to remember it has something to do with the logarithmic scale. I hope somebody here can answer it for me:

    A car accelerates from 0 to 60km/h in 4.2 seconds. What I'd like to know is how far the car has travelled (In metres) after the 4.2 seconds - when it has attained its 60km/h speed.

    We cannot assume a constant acceleration, as the speed increases gradually every second of the 4.2 seconds.

    Can anybody help with this?

    Cheers
    Nocturne
     
    Last edited: Nov 16, 2005
  2. jcsd
  3. Nov 16, 2005 #2

    Integral

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    Staff Emeritus
    Science Advisor
    Gold Member

    If we do not assume contant and do not have the rate of acceleration as a function of time there is not a unique answer to the question. The distance traveled is determined by the rate of acceleration.

    Assuming a contant acceleration you can use:
    [tex] x = \frac 1 2 a t^2 [/tex] with

    [tex] a = \frac { \Delta v } { \Delta t} = \frac {60 km/h} {4.2 s} [/tex]

    You will need to convert the 4.2 seconds to hours.
     
    Last edited: Nov 16, 2005
  4. Nov 16, 2005 #3

    russ_watters

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    Staff: Mentor

    You need to know what the acceleration of the car looks like, and that isn't that easy to find without making some pretty big assumptions.
     
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