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    A ball is projected upwards from a point which is 4m above the ground with speed 18ms-1. Find a)the speed of the ball when it is 15m above its point of projection, b)the speed with which the ball hits the ground.

    Which formula do you use to find out the first part of the question?
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    ignore the 4m.

    You have
    u(initial velocity) = 18
    a= - 9.81 ms-2 (it's negative, because ball is going upwards, against the gravity)
    s= 15m
    v(final velocity) = ?

    you need an equation that has u, a s and v. ----> v^2 = u^2 + 2as
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    (Original post by SomeStudent)

    you need an equation that has u, a s and v. ----> v^2 = u^2 + 2as
    Which equation would you use for the second part?
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    (Original post by Mist786)
    Which equation would you use for the second part?
    The same equation: v^2=u^2+2as
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    (Original post by Mist786)
    Which equation would you use for the second part?
    oh sorry, I didn't even see the question b :facepalm:

    for displacement, it's 15+4 = 19 so s = 19
    U (initial) becomes the answer to part a)
    a = 9.81
    v = ?

    so you have s u a v, therefore you're using the same equation

    M1 is tough at first, but with regular practise, it will get easier.
 
 
 
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