A lead bullet penetrates into a solid object and melts. Assuming that 40% of its kinetic energy is used to heat it, the initial speed of bullet is :
(Given : initial temperature of the bullet = 127$^\circ$C, Melting point of the bullet = 327$^\circ$C, Latent heat of fusion of lead = 2.5 $\times$ 104 J kg$-$1, Specific heat capacity of lead = 125 J/kg K)
Solution
<p>${2 \over 5} \times {1 \over 2}m{v^2} = mL + ms\Delta T$</p>
<p>$\Rightarrow {{{v^2}} \over 5} = 2.5 \times {10^4} + 125 + 200$</p>
<p>$\Rightarrow {{{v^2}} \over 5} = 5 \times {10^4}$</p>
<p>$\Rightarrow v = 500$ m/s</p>
About this question
Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law
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