1. You lift bricks, one at a time, onto a table. After a while, you begin to lift bricks slower and slower. As you slow down, does the energy you put into lifting each brick increase, decrease, or remain the same? What about the power you put into lifting each brick? The energy required to lift each block will remain the same, since you are lifting each identical one to the same height. However, since P = W/t, and the time required to lift each block is increasing, the power used to lift each block will decrease.

2. What was Joule's famous experiment regarding work and energy? What kind of energy was it? Explain the application of the First and the Second law of Thermodynamics in reference to the interchangeability between work and this kind of energy. Joule converted work into heat. He used gravitational energy of a weight dropping under gravity to rotate a wheel with blades to churn water. This caused the water to be warmed. Thus he converted work into heat energy. This follows the First law of Thermodynamics which states that Energy is conserved. According to Thermodynamics, work can be converted fully into heat, but heat can not fully be converted into work; Q = Q0 + W, a certain amount of heat, Q0 will come out, Q > Q0, if W > 0. This is in accordance with the Second law of Thermodynamics.

3. Imagine a 100% efficient automobile. Would it emit any exhaust? Is it possible to have such an automobile? Explain. A 100% efficient automobile will not emit any exhaust, since all of the heat would have been converted into work. But, such an automobile is not possible, since that will violate the Second law of Thermodynamics; whose outcome is no heat engine can be 100% efficient, or heat can not be fully converted into work.