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-   -   Total displacement (https://www.askmehelpdesk.com/showthread.php?t=397350)

  • Sep 17, 2009, 03:37 PM
    lillib123
    Total displacement
    A record of travel along a straigt path is as follows:
    a) Start from rest with constant acceleration of 3.06m/s2 for 19.8s;

    b) Constant velocty for the next .845 min;

    c) Constant negative acceleration of -9.12m/s2 for 4.46s.

    What is the total displacement x for the compete trip?
  • Sep 18, 2009, 05:55 AM
    ebaines

    The distance traveled for each of these segments can be calculated using the formulas:

    v = v0 + a*t;
    d = d0 + v0*t + 1/2 a*t^2

    Where d0 is the initial displacement at time t=0, and v0 is the initial velocity.

    Post back with the answer you get.
  • Sep 18, 2009, 05:10 PM
    lillib123

    I got 1069.26m, which is wrong. I tried finding the velocity for 1 and 2 with the first equation, and then found the distance and added them together. But it didn't work.
  • Sep 21, 2009, 06:47 AM
    ebaines

    I'll help you through the first two steps, and then you can take it from there.

    The distance traveled in the first segment is:

    D1 = 1/2 a t^2 = 1/2* 3.06m/s^2*(19.8m/s)^2 = 599.8 m

    The velocity at the end of the first segment:
    V1 = at = 3.06m/s^2 * 19.8 s = 60.6 m/s

    For the second segment, the distance traveled is: v1*t2 = 60.6 m/s * .845 min * 60 sec/mim = 3071.8 m.

    So the total displacement after the second segment is 599.8 m + 3071.8 m = 3671.6 m.

    Now, can you figure out the distance traveled in the third segment and add it to this?

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