Question

A hammer of mass 1kg having speed of 50 m/s, hit a iron nail of mass 200 gm. If specific heat of iron is 0.105 cal/gm°C and half the energy is converted into heat, the raise in temperature of nail is

• A. 7.1°C
• B. 9.2°C
• C. 10.5°C
• D. 12.1°C

Answer 1

Answer: (A)

7.1°C

Answer 2

$W = JQ$ ⇒ $\frac{1}{2}\left( \frac{1}{2}Mv^{2} \right) = J(m.c.\Delta\theta)$

⇒ $\frac{1}{4} \times 1 \times (50)^{2} = 4.2\lbrack 200 \times 0.105 \times \Delta\theta\rbrack$ ⇒ $\Delta\theta = 7.1{^\circ}C$