1. Your car's fuel efficiency is 35 miles per gallon. Assume that your car's fuel pump pulls fuel out of the fuel tank at a constant rate through a tube. If the speed of the fuel through the tube is equal to the speed of the car, what must be the cross-sectional area of the tube in square inches? What is it square millimeters? (Conversion factors: 1 gallon is equal to 231 cubic inches. For every mile traveled, the car uses a volume of fuel equal to the cross-sectional area of the tube × 1 mile. There are 12 inches per feet and 5280 ft per mile. How many inches are in a mile? How many cubic inches are in 1 square inches × 1 mile? There are 2.54 cm per inch.)
2. A steel sphere 3.0 cm in diamter has a mass of 0.11 kg. What is the mass of a steel sphere 5.0 cm in diameter?