Question

Of two masses of 5 kg each falling from height of 10 m, by which 2kg water is stirred. The rise in temperature of water will be

• A. 2.6°C
• B. 1.2°C
• C. 0.32°C
• D. 0.12°C

Answer 1

Answer: (D)

0.12°C

Answer 2

$W = JQ$ ⇒ $(2m)gh = J \times m^{'}c\Delta\theta$

⇒ $2 \times 5 \times 10 \times 10 = 4.2(2 \times 1000 \times \Delta\theta)$

⇒ $\Delta\theta = 0.1190{^\circ}C = 0.12{^\circ}C$