Dimensional Analysis WS 4

Document Sample
Dimensional Analysis WS 4 Powered By Docstoc
					Dimensional Analysis WS 4      Name ________________________ Hour _____

1. In 2004 Iowa farmers harvested over 12 million acres of corn. If 183 bushels of corn
can be harvested from an acre of land, 1 bushel of corn weighs 56 lbs, and 3 ears of corn
weigh a pound, how many ears of corn were produced by Iowa farmers in 2004? Answer
is ≈ 3.7 x 1011 ears of corn.

2. By some estimates, the average American consumes 55 gallons of soda each year. If
a 12-ounce can of soda contains about 40 g of sugar, how many pounds of sugar from
sodas does each American consume in a year? Answer is ≈ 52 lbs.

3. It is estimated that in 1993 about 5.5 x 109 fast food burgers were consumed in the
U.S. If the typical burger weighs about 3.0 ounces and the typical cow produces 100 lbs
of hamburger, how many cows were slaughtered for burgers each day? Answer is ≈ 2.8 x
104 cows.

4. A physics student comes to class every day with a 16-ounce bottle of Dr. Pepper. How
many gallons of soda does he consume in one school year? Assume a school year has
180 days. Answer is ≈ 22.5 gallons.

5. About 10,800 corn plants, each requiring about 180 L of water to grow from seed to
harvest, can be grown on an acre of land. How many gallons of water are needed to grow
600. acres of corn? Answer is ≈ 3.08 x 108 gallons.

Astronomers often use units of measure much larger than those typically used
for everyday purposes. An astronomical unit (AU) is used to measure distances
typically within a solar system. An AU is ≈ 93,000,000 miles. Two units of
measure commonly used for greater distances are the light year (ly) and the
parsec (pc). A light year is ≈ 5.878x1012 miles and is often used to measure
distances between solar systems. The parsec is ≈ 1.9174x1013 miles and is used
to measure intergalactic distances, although the light year is often used to
measure intergalactic distances too.

6. Proxima Centauri, our nearest star other than our sun, is roughly 1.294 pc away. How
far away is this in meters?

7. If light travels approximately 3.00 x 108 m/s, how many years does it take the image
of Proxima Centauri to reach your eyes?

8. Some believe that humans will colonize the deep reaches of space in the future. If a
spacecraft achieves a speed of 35,000 mi/h, how many years will it take to reach Proxima
Centauri?

9. Some estimate that the average person requires about 64 ounces of water each day.
How many gallons of water would a 25 year-old astronaut consume if he lives until 75
years old?