In a game of football outdoors on a cold day, a player will begin to feel exhausted after using approximately 8.0 × 105 J of internal energy.
(a) One player, dressed too lightly for the weather, has to leave the game after losing 6.8 × 105 J of heat. How much work has he done?
(b) Another player, wearing clothes that offer better protection against heat loss, is able to remain in the game long enough to do 2.1 × 105 J of work. What is the magnitude of the heat that he has lost?