Question

A body of mass 25 kg is dragged on a rough horizontal floor for one hour with a speed of2 kmh^–1. The coefficient of friction for the surface in contact is 0.5 and half the heat produced is absorbed by the body. If specific heat of body is

0.1 cal g^–1 (⁰C^–1) and g = 9.8 ms^–2, then the rise in temperature of body is:

• A. 39 K
• B. 59.5 K
• C. 84.5 K
• D. 11.6 K

Answer 1

Answer: (D)

11.6 K

Answer 2

0.5 × mMg × (V × 60 × 60) = MSDT

DT = $\frac{0.5 \times 0.5 \times 9.8 \times 2 \times \frac{5}{18} \times 60 \times 60}{0.1 \times 4.186 \times 10^{3}}$