A 50-kg iron block and a 20-kg copper block, both initially at 80°C, are dropped into a large lake at 15°C. Thermal equilibrium is established after a while as a result of heat transfer between the blocks and the lake water. Assuming the surroundings to be at 20°C, determine the amount of work that could have been produced if the entire process were executed in a reversible manner.

The amount of work produced by the entire process of cooling the iron and the copper is 1969.5 kJ

Explanation:

Given;

mass of iron = 50 kg

mass of copper = 20 kg

initial temperature of iron and copper = 80 °C

temperature of the lake = 15°C

Both iron and copper forms a closed system and attained thermal equilibrium.

This energy balance can be expressed as;

Net heat transfer = change in internal energy

Δ = Δ + Δ

And U = McΔT

C is specific heat capacity; ( iron = 0.45 kJ/kg.K, copper = 0.39 kJ/kg.K)

ΔU = 50 x 0.45 (80 -15) +  20 x 0.39 (80 -15)

ΔU = 1462.5 kJ + 507 kJ = 1969.5 kJ

The amount of work produced by the entire process of cooling the iron and the copper is 1969.5 kJ

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge