What is the change in internal energy (in J) of a system that does 4.50 ✕ 105 J of work while 3.00 ✕ 106 J of heat transfer occurs into the system, and 7.00 ✕ 106 J of heat transfer occurs to the environment?

A model steam engine of 1.00 kg mass pulls eight cars of 1.00 kg mass each. The cars start at rest and reach a velocity of6.20 m/s in a time of 3.00 s while moving a distance of 4.50 m. During that time, the net heat input is 128 J. What is the change in the internal energy of the engine? In Joules

1. Suppose a woman does 500 J of work and -9400 J of heat transfer occurs into the environment in the process. (a) What is the decrease in her internal energy, assuming no change in temperature or consumption of food? (That is, there is no other energy transfer.) ΔΕint ✓ J (b) The internal energy is stored energy due to food intake. Treating the change in internal energy as the input energy and work done as output, what is her efficiency? Efficiency, Eff: % (c) What physics law did you use in this problem? Zeroth Law of Thermodynamics First Law of Thermodynamics Second Law of Thermodynamics

In a game of football outdoors on a cold day, a player will begin to feel exhausted after using approximately 8.0 x 10 J of internal energy. (a) One player, dressed too lightly for the weather, has to leave the game after losing 7.0 x 10° Jof 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 2.3x 105 J of work. What is the magnitude of the heat that he has lost? (a) Number Units (b) Number Units <.