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    hi there
    im just wondering how i would go about finding the speed when i have 2 velocities and acceleration
    i know speed = displacment/time and displacment = velocity x time but i have 2 different velocities.
    for example:
    i am given the initial velocity = 2i
    i am given the acceleration = i
    i worked out the end velocity = 5i
    time = 3 seconds

    i have tried a few different ways but none give me the right answer
    and i can't find an example similar in the book

    any help is much appreciated
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    What's the full question? I'm not sure what you need to find.

    Are you talking about relative velocities?
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    "a particle P has velocity u initially and acceleration a. Find the velocity and the speed after t seconds when:
    u = 2i, a = i, t = 3"

    and ive found the velocity for all of them (this one is 5i)
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    Well, it's initial velocity is 2i, after another 3 seconds accelerating at i, then the final velocity will be 5i yes.

    Velocity is a vector btw, while speed is a scalar.

    So, while the velocity is 5i (magnitude and direction) the speed is simply 5.
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    hi there
    thank you for your reply
    one question though, why would the speed not be 5/3 given that it gives you the time to be 3 seconds? sorry if this is an obvious answer :unsure:
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    (Original post by confusedmathsguy)
    hi there
    thank you for your reply
    one question though, why would the speed not be 5/3 given that it gives you the time to be 3 seconds? sorry if this is an obvious answer :unsure:
    speed is the magnitude of velocity.... just the '5' bit of '5i'
 
 
 
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