A body cools from 8 0 ∘ C to 7 0 ∘ C in 10 minutes in a room at 3 0 ∘ C. Using Newton's law, find its temperature in ∘ C at the end of the next 10 minutes (nearest whole number).

First: 10 10 = k ( 75 − 30 ) , so k = 45 1 . Second: 10 70 − T = 45 1 ( 2 70 + T − 30 ) = 90 T + 10 . So 630 − 9 T = T + 10 and T = 6 2 ∘ C.

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Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoHeat TransferHard2 min

PhysicsHardinteger

A body cools from $8 0^{\circ}$ C to $7 0^{\circ}$ C in 10 minutes in a room at $3 0^{\circ}$ C. Using Newton's law, find its temperature in $^{\circ}$ C at the end of the next 10 minutes (nearest whole number).

Answer:

Solution:

First: $\frac{10}{10} = k (75 - 30)$ , so $k = \frac{1}{45}$ . Second: $\frac{70 - T}{10} = \frac{1}{45} (\frac{70 + T}{2} - 30) = \frac{T + 10}{90}$ . So $630 - 9 T = T + 10$ and $T = 6 2^{\circ}$ C.

Subject:PhysicsTopic:Heat & ThermoSubtopic:Heat Transfer

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