Answer the following questions.

1. What is the difference between a round disk and a wheel?
2. Why are wheels sometimes attached to pianos?
3. Why are wheels attached to wheelbarrows?
4. What is a pulley?
5. What is the purpose of a pulley?
6. Where are pulleys used?
7. What kind of wheel is a car's steering wheel an example of?
8. What is the device used in winding things?