2007-01-16 18:35:11 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
from the first law of thermodynamics, we have dQ= dU+dW.
dQ= -6.8(units)+2.5(units)= -4.3(units)..the negative sign indicates fall or drop in the enrgy levels...
hence, the amt . of heat lost by the man is 4.3 x 10^5 J
2007-01-16 18:48:36 · answer #1 · answered by pran diabolic 1 · 0⤊ 0⤋
The energy decrease went into work and heat. The amount that went into heat is the difference between the energy spent and the energy into work. You can express the result in calories using the conversion from joules to calories: 1 calorie = 4.184 joules
2007-01-16 18:51:05 · answer #2 · answered by gp4rts 7 · 0⤊ 0⤋
dE = dQ + dW
change in energy (-6.8x10^5) is equal to change in heat + work done (-2.5x10^5)
therefore
dQ = dE-dW
negative is given, positive is absorbed
2007-01-16 18:51:34 · answer #3 · answered by Anonymous · 0⤊ 0⤋