A 25.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 21.00 m. When she is partway down the slide

Question

A 25.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 21.00 m. When she is partway down the slide, at a height h2 of 8.00 m, she is moving at a speed of 7.80 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.).

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Cherry 2 weeks 2021-07-19T14:29:14+00:00 1 Answers 2 views 0

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    2021-07-19T14:31:04+00:00

    Answer:

    The mechanical energy lost due to friction is 2,424.5 J

    Explanation:

    Given;

    mass of the child, m = 25 kg

    intial velocity of the child, u = 0

    final velocity of the child, v = 7.8 m/s

    initial position of the child, h₁ = 21 m

    final position of the child, h₂ = 8 m

    Let the energy lost due to heat = ΔE

    ΔE + ΔK.E  + ΔP.E = 0

    ΔE  +   ¹/₂m(v² – u²)  +  mg(h₂ – h₁) = 0

    ΔE   +   ¹/₂ x 25(7.8² – 0)    +   25 x 9.8(8 – 21) = 0

    ΔE   +  760.5 J   – 3185 J =

    ΔE   –  2,424.5 J = 0

    ΔE = 2,424.5 J

    Therefore, the mechanical energy lost due to friction is 2,424.5 J

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