A force of 70 N is applied to a 28 kg rock causing it to slow down from 25 m/s to 15 m/s, a change in velocity of 10 m/s. How long was that

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A force of 70 N is applied to a 28 kg rock causing it to slow down from 25 m/s to 15 m/s, a change in velocity of 10 m/s. How long was that force applied?

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Thu Thủy 5 months 2021-08-19T19:40:03+00:00 1 Answers 0 views 0

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    2021-08-19T19:41:04+00:00

    Answer: 4 s

    Explanation:

    Given

    The applied force is 70 N

    mass of the rock is 28 kg

    initial velocity u=25\ m/s

    final velocity v=15\ m/s

    Deceleration provided by force is

    a=-\dfrac{70}{28}=-2.5\ m/s^2

    using the equation of motion

    v=u+at\\\Rightarrow 15=25-2.5t\\\Rightarrow 2.5t=10\\\Rightarrow t=4\ s

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