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Lead bullet heated to its melting point and melted

This type of question, asked 2 times: 27 Jun 2022, 23 Jan 2025. All 2 questions below, oldest first.

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  1. Question 1

    27 Jun 2022

    99
    A lead bullet penetrates into a solid object and melts. Assuming that 40%40\% of its kinetic energy is used to heat it, the initial speed of bullet is: (Given, initial temperature of the bullet =127∘C=127^{\circ}C, Melting point of the bullet =327∘C=327^{\circ}C, Latent heat of fusion of lead =2.5×104 JKg−1= 2.5 \times10^{4}\text{ }JKg^{- 1}, Specific heat capacity of lead =125 J/kgK= 125\text{ }J/kgK )

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  2. Question 2

    23 Jan 2025

    12
    A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet having melting temperature of 600 K penetrates into the block and melts down. If the total heat required for the process is 625 J , then the mass of the bullet is _____\_\_\_\_\_ grams. (Latent heat of fusion of lead =2.5×104JKg−1= 2.5 \times10^{4}JKg^{- 1} and specific heat capacity of lead =125JKg−1 K−1= 125JKg^{- 1}{\text{ }K}^{- 1} )

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