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  1. Yaseen Khan
    Yaseen Khan :
    5 years ago

    Given Data:
    vi = 20m/sec
    vf = 0m/sec
    S = 40m
    t = ?

    Solution:
    We know that,
    S=vi * t + 1/2at^2.
    But , Here , a=?

    We know that,
    2aS = vf^2 - vi^2.

    2 * a * 40 = 0 - 20^2.
    a = - 400/80 = -5m/sec^2.

    Now putting values in eqn S = vi * t + 1/2at^2.
    40m = 20 * t + (-5 * t^2)/2.
    40m = 20t - 2.5t^2.
    25t^2 - 200t + 400 = 0.
    t^2 - 8t + 16 = 0.
    (t-4)^2=0.
    t - 4 = 0.
    t = 4sec-> Ans

Related Questions on Applied Mechanics and Graphic Statics

The resultant of two forces P and Q acting at an angle $$\theta $$, is

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