A lead bullet melts on hitting a fixed target. What will be the minimum speed of the bullet, if it is assumed that the heat produced is retained entirely by the bullet? Initial temperature of the bullet = `47.6^(@)C`, specific heat of lead = `0.03 cal cdot g^(-1) cdot^(@)C^(-1)`, melting point of lead = `327^(@)C`, latent heat of fusion of lead = `6 cal cdot g^(-1) , J = 4.2 xx 10^(7) erg cdot cal^(-1)`.

Answer

`3.475 xx 10^(4) cm cdot s^(-1)`