A 1200-kg car comes to rest from a speed of 25 m/s in a distance of 75 m. If the brakes are the only thing making the car come to a stop, ca

Question

A 1200-kg car comes to rest from a speed of 25 m/s in a distance of 75 m. If the brakes are the only thing making the car come to a stop, calculate the magnitude of the force that the brakes apply on the car.

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Eirian 3 years 2021-08-19T09:11:17+00:00 1 Answers 11 views 0

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    2021-08-19T09:12:39+00:00

    Answer:

    5000 N

    Explanation:

    First we need to calculate the acceleration the car had.

    We can do that using Torricelli formula:

    V^2 = Vo^2 + 2aDS,

    where V = 0, Vo = 25, DS = 75

    0 = 25^2 + 2*a*75

    150a = -625

    a = -4.1667 m/s^2

    The force is calculated multiplying the mass and the acceleration, so:

    F = m*a = 1200 * (-4.1667) = -5000 N

    The magnitude of the break force is 5000 N (the sign only indicates the direction, the magnitude is only the value without sign)

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