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Math Help - Find an expressjon for velocity?

  1. #1
    Super Member fardeen_gen's Avatar
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    Find an expressjon for velocity?

    In a car race, car A takes a time of t sec less than car B at the finish and passed the finishing point with a velocity v m/s more than the car B. Assuming that the cars start from rest and travel with constant acceleration a1 and a2 respectively which of the following is correct?

    A) v = t√(a1/a2)
    B) v = t√(a1.a2)
    C) v = t /√(a1.a2)
    D) v = t√(a2/a1)
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  2. #2
    Senior Member nikhil's Avatar
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    Quote Originally Posted by fardeen_gen View Post
    In a car race, car A takes a time of t sec less than car B at the finish and passed the finishing point with a velocity v m/s more than the car B. Assuming that the cars start from rest and travel with constant acceleration a1 and a2 respectively which of the following is correct?

    A) v = t(a1/a2)
    B) v = t(a1.a2)
    C) v = t /(a1.a2)
    D) v = t(a2/a1)
    For A
    acceleration=a1
    total time=t'-t
    final velocity=u+v

    For B
    acceleration=a2
    total time=t'
    final velocity=u

    s=(1/2)a1(t'-t)^2=(1/2)a2(t')^2
    therfor
    1)(1-t/t')=(a2/a1)^(1/2)
    also
    (u+v)^2=2a1s
    (u)^2=2a2s
    dividing both we get
    2)(1+v/u)=(a1/a2)^(1/2)
    but u=a2t'
    so substitute this value in 2) and put value of t' from 1)
    your FINAL ANSWER WILL BE
    v=t(a1a2)^(1/2) thats option B
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