Answer:
672000 J.
Step-by-step explanation:
From the question,
q = cm(t₂-t₁)............................ Equation 1
Where q = heat energy supplied to the water, c = specific heat capacity of water, m = mass of water, t₂ = final temperature, t₁ = Initial temperature.
Given: m = 8.0 kg, c = 4200 J/kg°C, t₂ = 40°C, t₁ = 20°C
Substitute these values into equation 1
q = 8×4200×(40-20)
q = 8×4200×20
q = 672000 J.
Hence the energy suplied to the water is 672000 J.