A piece of iron block moves across a rough horizontal surface before coming to rest. The mass of the block is 1.3 kg, and its initial speed

Question

A piece of iron block moves across a rough horizontal surface before coming to rest. The mass of the block is 1.3 kg, and its initial speed is 4.0 m/s. How much does the block’s temperature increase, if it absorbs 71% of its initial kinetic energy as internal energy? The specific heat of iron is 452 J/(kg · °C).

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RuslanHeatt 3 years 2021-08-31T00:33:02+00:00 1 Answers 10 views 0

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    2021-08-31T00:34:20+00:00

    Answer:

    0.0126°C

    Explanation:

    Kinetic energy sustain by the block,K.E = 1/2× mass×velocity^2

    K.E = 1/2 ×1.3×(4^2)

    =1/2 × 1.3× 16 = 1.3 ×8 = 10.4J

    The internal energy is 71% of kinetic energy is;

    U= 71/100 × 10.4 = 7.38J

    But U = m × C × ∆T

    Where U is internal energy

    m is the mass of iron

    C is the heat capacity of iron

    ∆T is the temperature change

    By make ∆T the subject of the formula we have

    ∆T=U/ m×C

    =7.38/ 1.3×452= 0.0126°C

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