Lesson: The First Law of Thermodynamics

A rope is pulled, increasing its tension. The work done pulling the rope is 23 J. While being pulled, the rope is also heated by the hand of the person pulling on it, by a net 1.5 J. What is the change in the rope’s internal energy? Give your answer to three significant figures.

A cylinder contains a gas that receives net heating of 15 J. While the gas is heated, the lid of the cylinder is moved upward through a distance of 15 cm, as shown in the diagram. The mass of the lid is 1.45 kg. How much does the internal energy of the gas increase during the heating? Answer to two significant figures.