A glass of boiling water weighing 250 g is cooled to 20 degrees Celsius and releases energy.

A glass of boiling water weighing 250 g is cooled to 20 degrees Celsius and releases energy. Calculate the height to which a body weighing 1 kg could be lifted using this energy.

Data: m1 (mass of a glass of boiling water) = 250 g (0.25 kg); t (boiling water temperature) = 100 ºС; tк (temperature to which the boiling water has cooled down) = 20 ºС; m2 (mass of the lifted body) = 1 kg.

Constants: C (specific heat capacity of water) = 4200 J / (kg * ºС); g (acceleration due to gravity) ≈ 10 m / s2.

The height to which the body can be lifted is determined from the equality: Q = C * m1 * (t – tк) = ΔЕп = m2 * g * h and h = C * m1 * (t – tк) / (m2 * g) …

Calculation: h = 4200 * 0.25 * (100 – 20) / (1 * 10) = 8400 m (8.4 km).