(b) $mc$ ($\mathrm{\Delta}T) = \frac{\frac{1}{2}\left( \frac{1}{2}m\ v^{2} \right)}{J}$ $\mathrm{\Delta}T = \frac{v^{2}}{4Jc} = \ \frac{480 \times 480}{4 \times 4.2 \times (0.03 \times 10^{3})} = 457℃$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.