Question

In a hot day's rece, a bicyclist consumes 7.4 L of water over the span af 3 5 hours Making the approximation that all of the cyclist's energy goes into evaporeting this water as sweat, how much energy in kcal did the rider use during the ride? (Since the ettirency ot me nder is only about r % most ot the energy ro sumed does go to hear, so our approximat on is not tar ott Assume that the nest ot vaponzation at com temperature 1s 585 keal/kg Express your answer using two significant figures. kcal

Answer 1

Solution :-

           The value of the heat of vaporization from the body at room temperature

L   = 585kcal/kg       for the latent heat of vaporization of water at room temperature

         If all the energy supplied by the cyclist evaporates to water, we have

                                     Q = m L

                                           = 7.4 L * ( 1 kg / 1L ) * 585 x 10³ cal

                                          = 4.3 x 10^3 kcal