Charles' law explains which of these phenomena?
a. why a balloon deflates when the air around it cools
b. why solids require heat in order to change into gases
c. why the pressure of a gas increases when volume decreases
d. why some gases only react with each other at high temperatures

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?

What is the stall speed at sea level of an airplane that weights 10000 lbs., has a wing area of 300ft^2, and a maximum lift coefficient of 1.4? what is the stall speed if flaps that double cl,max are applied?

What distance does a car travel as its speed changes from 0 to 20 m/s in 17 s at constant acceleration?