1. Which, if any, of the following objects does not exert a gravitational force on you?
- this book
- the Sun
- the nearest star
- a distant galaxy
- the Atlantic ocean
2. In what sense is the Newtonian universe simpler than Ptolemy's? Suppose observations had shown that the two did equally well at explaining the data. Construct an argument to say that Newton's universe should still be preferred.
3. How does gravity affect the flow of blood in your body? The flow of sap in trees? How have organisms evolved to counteract the force of gravity?
4. How does a sundial work? How would you build a sundial differently in Canada from one in Mexico?