In exercising, a weight lifter loses 0.153 kg of water through evaporation, the
ID: 1702458 • Letter: I
Question
In exercising, a weight lifter loses 0.153 kg of water through evaporation, the heat required to evaporate the water coming from the weight lifter's body. The work done in lifting weights is 1.60 x 105 J. (a) Assuming that the latent heat of vaporization of perspiration is 2.42 x 106 J/kg, find the change in the internal energy of the weight lifter. (b) Determine the minimum number of nutritional Calories of food that must be consumed to replace the loss of internal energy. (1 nutritional Calorie = 4186 J).Explanation / Answer
U=Q+W Q=mL=0.153x2.42x106=370260 W=1.13x105 U=483260 change in internal energy=4.83x10^5J nx4186=483260 n=115.446 nutritional calories