g student pushes a 80 Kg crate across the classroom floor a distance 5 m at constant speed of 0.4 m/s . If the coefficient of kinetic fricti

Question

g student pushes a 80 Kg crate across the classroom floor a distance 5 m at constant speed of 0.4 m/s . If the coefficient of kinetic friction between the crate and the floor is 0.9, how much work did she do

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Huyền Thanh 4 years 2021-08-05T03:07:19+00:00 1 Answers 8 views 0

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  1. dangkhoa
    0
    2021-08-05T03:08:33+00:00
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    Answer: The work done is W = 3528J.

    Explanation: Work (W) is an amount of energy used to do determined movement. To calculate it, we use the formula, as the movement is horizontal:

    W = F.d, where

    F is force on the object

    d is distance it went through.

    The force acting on the crate is due to friction.

    F_{f} = μ . F_{N}

    μ is the kinetic friction

    F_{N} is the normal force

    There is no up and down movement, so F_{N} = F_{g}, with g = 9.8m/s²

    F_{f} = μ . m . g

    F_{f} = 0.9 . 80 . 9.8

    F_{f} = 705.6 N

    Substituing F_{f}  into the work formula, we have:

    W = F_{f} . d

    W = 705.6 . 5

    W = 3528 J

    The work done to move the crate across a distance of 5m is 3528 J.

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