At a fabrication plant, a hot metal forging has a mass of 75 kg and a specific heat

capacity of 430 J / (kg? C°). To harden it, the forging is immersed in 710 kg of oil that has

a temperature of 32 °C and a specific heat capacity of 2700 J / (kg? C°). The final

temperature of the oil and forging at thermal equilibrium is 47 °C. Assuming that heat

flows only between the forging and the oil, determine the initial temperature of the

forging.

(5)

Question

Physics

Layne Adkins

31 August, 08:06

At a fabrication plant, a hot metal forging has a mass of 75 kg and a specific heat

capacity of 430 J / (kg? C°). To harden it, the forging is immersed in 710 kg of oil that has

a temperature of 32 °C and a specific heat capacity of 2700 J / (kg? C°). The final

temperature of the oil and forging at thermal equilibrium is 47 °C. Assuming that heat

flows only between the forging and the oil, determine the initial temperature of the

forging.

(5)

+2

Answers (1)

Know the Answer?

Journey Turner · Answer 1

940°C

Explanation:

Heat lost by the forging = heat gained by the oil

-mCΔT = mCΔT

- (75 kg) (430 J/kg/°C) (47°C - T) = (710 kg) (2700 J/kg/°C) (47°C - 32°C)

-32250 (47°C - T) = 1917000 (15°C)

47°C - T = - 892°C

T = 939°C

Rounded to two significant figures, the initial temperature is 940°C.