Which of the following statements is true? a. like charges attract and unlike charges repel each other. b. gravitational forces only exist between large masses. c. on a level surface, normal force is greater than the weight of the object. d. applied forces are those created by another object or person.

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.