In a rollercoaster, the first hill is always the tallest. Subsequent hills are never as tall as the first. Why? What would happen to the rollercoaster cart
if the second, third, etc. hills were taller?

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.