In lab you submerge 100 g of 40°C iron nails in 100 g of 20°C water (the specific heat of iron is 0.12 cal/g°C.)
(a) Equate the heat gained by the water to the heat lost by the nails and show that the final temperature of the water becomes 22.1°C.
(b) Your lab partner is surprised by the result and says that since the masses of iron and water are equal, the final water temperature should lie closer to 30°C, half-way between. What is your explanation?