A ball is kicked horizontally with a speed of 5.0 ms-1 from the roof of a house 3 m high. When will the ball hit the ground?

Question

A ball is kicked horizontally with a speed of 5.0 ms-1 from the roof of a house 3 m high. When will the ball hit the ground?

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Edana Edana 1 year 2021-09-03T04:17:39+00:00 1 Answers 35 views 0

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    2021-09-03T04:18:56+00:00

    Answer:

    the time taken for the ball to hit the ground is 0.424 s

    Explanation:

    Given;

    velocity of the ball, u = 5 m/s

    height of the house which the ball was kicked, h = 3m

    Apply kinematic equation;

    h = ut + ¹/₂gt²

    where;

    h is height above ground

    u is velocity

    g is acceleration due to gravity

    t is the time taken for the ball to hit the ground

    Substitute the given values and solve for t

    3 = 5t + ¹/₂(9.8)t²

    3 = 5t + 4.9t²

    4.9t² + 5t -3 = 0

    a = 4.9, b = 5, c = -3

    Solve for t using formula method

    [tex]t = \frac{-5 +/-\sqrt{5^2-4(4.9*-3)}}{2(4.9)} = \frac{-5+/-(9.154)}{9.8} \\\\t = \frac{-5+9.154}{9.8} \ or \ \frac{-5-9.154}{9.8} \\\\t = \frac{4.154}{9.8} \ or \ \frac{-14.154}{9.8} \\\\t = 0.424 \ sec \ or -1.444 \ sec\\\\Thus, t = 0.424 \ sec[/tex]

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