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° C, Melting point of the bullet =327° C, Latent heat of fusion of lead =2.5 × 104 J Kg -1, Specific heat capacity of lead =125 J / kg K )

Question

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° C, Melting point of the bullet =327° C, Latent heat of fusion of lead =2.5 × 104 J Kg -1, Specific heat capacity of lead =125 J / kg K ) (A) 125 ms -1 (B) 500 ms -1 (C) 250 ms -1 (D) 600 ms -1

Tardigrade Admin · Accepted Answer

m × 125 × 200+ m × 2.5 × 104=(1/2) mv 2 × (40/100) V =500 m / s

$125 m s^{- 1}$

$500 m s^{- 1}$

$250 m s^{- 1}$

$600 m s^{- 1}$

$m \times 125 \times 200 + m \times 2.5 \times 1 0^{4} = \frac{1}{2} m v^{2} \times \frac{40}{100}$
$V = 500 m / s$

125ms−1

500ms−1

250ms−1

600ms−1

m×125×200+m×2.5×104=21​mv2×10040​ V=500m/s

$125 m s^{- 1}$

$500 m s^{- 1}$

$250 m s^{- 1}$

$600 m s^{- 1}$

$m \times 125 \times 200 + m \times 2.5 \times 1 0^{4} = \frac{1}{2} m v^{2} \times \frac{40}{100}$
$V = 500 m / s$