El valor de 678040 se escribe en notación científica a. 6,78 x 10 5
b. 6,78 x 10 4
c. 67,8 x 10 6

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

Why is metal often used for cooking pan?

The earth is constantly spinning on its axis, like you might spin a basketball on your finger. it is this spinning of the earth that causes