Distinguish between the concepts of internal energy and temperature.

An athlete loses 1.8 kg of water from her body through sweating during a training session that lasts one hour.

Estimate the rate of energy loss by the athlete due to sweating. The specific latent heat of evaporation of water is 2.3×10⁶ J kg^–1.

internal energy:
total energy of component particles (in the human);
comprises potential energy + (random) kinetic energy;

temperature: 
measure of average kinetic energy of particles;
indicates direction of (natural) flow of thermal energy;
internal energy measured in J and temperature measured
in K/°C ; (both needed)

(accept alternative suitable units)   

total energy lost=2.3×10⁶×1.8(=4.14×10⁶J);
1.2 kW;