A useful and easy-to-remember approximate value for the number of seconds in a year is π × 107. Determine the percent error in this approximate value. (There are 365.24 days in one year.)

Estimate the average speed with which the hair on your head grows. Give your answer in both m/s and m/hour. Briefly describe how you arrived at this estimate.

As an architect, you are designing a new house. A window has a height between 140 cm and 150 cm and a width between 74 cm and 70 cm. What are the smallest and largest areas that the window could be?

How many significant figures are there in each of the following values? (d) 0.07 x 10^8

How many significant figures are there in each of the following values? (c) 75.0

With a wooden ruler, you measure the length of a rectangular piece of sheet metal to be 12 mm. With micrometer calipers, you measure the width of the rectangle to be 5.98 mm. Use the correct number of significant figures: What is (c) the perimeter of the rectangle?

You are using water to dilute small amounts of chemicals in the laboratory, drop by drop. How many drops of water are in a 1.0-L bottle?

How many times does a human heart beat during a person's lifetime? How many gallons of blood does it pump?

Four astronauts are in a spherical space station. (a) If, as is typical, each of them breathes about 500 cm3 of air with each breath, approximately what volume of air (in cubic meters) do these astronauts breathe in a year?