Question 260: Properties of Matter

Question

A body cools from 60$$^\circ$$C to 40$$^\circ$$C in 6 minutes. If, temperature of surroundings is 10$$^\circ$$C. Then, after the next 6 minutes, its temperature will be ____________$$^\circ$$C.

Accepted Answer

By average form of Newton's law of cooling $\frac{20}{6}=\mathrm{k}(50-10)$
$\frac{40-\mathrm{T}}{6}=\mathrm{K}\left(\frac{40+\mathrm{T}}{2}-10\right)$
From equations (i) and (ii)
$\frac{20}{40-\mathrm{T}}=\frac{40}{10+\mathrm{T} / 2}$
$10+\frac{\mathrm{T}}{2}=80-2 \mathrm{~T}$
$\frac{5 \mathrm{~T}}{2}=70 \Rightarrow \mathrm{T}=28^{\circ} \mathrm{C}$

Properties of Matter

A body cools from 60$^\circC to 40^\circC in 6 minutes. If, temperature of surroundings is 10^\circC. Then, after the next 6 minutes, its temperature will be ____________^\circ$C.

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