1. Is it possible to determine the degree of skill of a trade by the number of tools used? Explain.

2. What impression would you gather from a person who was driving carpet tacks with a machinist's hammer? Explain.

3. Is it economical to use a sledge hammer to drive ordinary wire nails into a board floor? Explain.

4. State the kind of energy used in the following cases: (a) a man lifts a casting from the floor; (b) a house is moved with horses; (c) a grist mill grinds corn by means of running water back of the mill; (d) a steam boiler drives the engine.

5. Has a mechanic more energy in the morning before going to work than after a day's work? Explain.