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    can't do this dam question although im sure its not too difficult.

    tennis ball his so that it moves vertically downwards from a height of 1m with an initial speed of 5ms^-1. when it hits the ground it rebounds vertically with half the speed it had when it hit the ground.

    Q - find the height to which it rebounds
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    (Original post by ShOcKzZ)
    can't do this dam question although im sure its not too difficult.

    tennis ball his so that it moves vertically downwards from a height of 1m with an initial speed of 5ms^-1. when it hits the ground it rebounds vertically with half the speed it had when it hit the ground.

    Q - find the height to which it rebounds
    First, find the speed it hits the ground using the formula v^2=(u^2)+2as.

    distance s=1 initial speed u=5 acceleration down a=g

    so v^2=25+2g

    Now consider its upwards flight.

    u^2=(25+2g)/4 a=-g and v=0 at the max height.

    Now using the same formula we can find s.

    s=((v^2)-(u^2))/2a = (0-(25+2g))/-8g = (25+2g)/8g= 57cmto 2 sf.

    (this is taking g as 9.8)
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    eh, excuse me for asking but wheres my damn rep?
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    (Original post by ShOcKzZ)
    can't do this dam question although im sure its not too difficult.

    tennis ball his so that it moves vertically downwards from a height of 1m with an initial speed of 5ms^-1. when it hits the ground it rebounds vertically with half the speed it had when it hit the ground.

    Q - find the height to which it rebounds
    On path to hit ground:

    s = 1, u = 5, a = 9.8

    v^2 = 5^2 + (2 * 9.8 * 1)
    v^2 = 25 + 19.6
    v = sq.root (44.6)
    v = 6.68 ms^-1 (3 sf)

    On way back up to reach max height:
    (Remember its initial speed on way back up is then halved)

    u = 3.34, a = -9.8, v = 0,

    0 = (3.34)^2 + (2 * -9.8 * s)
    0 = 11.1556 - 19.6s
    19.6s = 11.1556
    s = (11.1556)/19.6
    s = 0.569 m (3.s.f.)

    Therefore the ball rebounds to a height of 56.9 cm (3.s.f)
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    still no rep for you guys?
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    (Original post by TheWolf)
    still no rep for you guys?
    I don't want rep, I just wanted to do the question for my own benefit
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    (Original post by bono)
    I don't want rep, I just wanted to do the question for my own benefit
    lol and youve got enough reps anyways, like me
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    (Original post by TheWolf)
    lol and youve got enough reps anyways, like me
 
 
 
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