32
Use of Dimensions
PROBLEMS B
7. For each of the following pairs of units, follow the same procedure as that for
Problem 6.
(a) cubic feet to gallons
(b) ounces per square foot to pounds per square yards
(c) gallons per second to cubic yards per minute
(d) tons per cubic foot to pounds per cubic inch
(e) yards per second to inches per hour
(f) dollars per pound to nickels per ounce
(g) miles to mils (1 mil = 1/1000 in)
(h) knots to miles per hour (1 knot = 101.5 feet per minute)
(i) degrees of arc per second to revolutions per minute
8. An acre-foot of water will cover an acre of land with a layer of water one foot
deep. How many gallons are in an acre-foot? Use the following factors: 1 acre
= 4840 yd
2 ; and 1 gal = 231 in
3 .
9. Municipal water is sold at 21 cents per 100 cu ft. What is the price per
acre-foot?
10. In the Bohr model of the hydrogen atom, an electron travels in a circular orbit
about the nucleus at approximately 5 x 10
(> miles per hour. How many revolutions per second does the electron make if the radius of the orbit is 2 x 10"
9
inches?
11. A light-year is the distance that light travels in one year at a velocity of
186,000 miles per second. How many miles is it to the galaxy in Andromeda,
which is said to be 650,000 light-years away?
12. A parsec is a unit of measure for interstellar space: it is equal to 3.26 lightyears. How many miles are in one parsec?
Use of Dimensions
PROBLEMS B
7. For each of the following pairs of units, follow the same procedure as that for
Problem 6.
(a) cubic feet to gallons
(b) ounces per square foot to pounds per square yards
(c) gallons per second to cubic yards per minute
(d) tons per cubic foot to pounds per cubic inch
(e) yards per second to inches per hour
(f) dollars per pound to nickels per ounce
(g) miles to mils (1 mil = 1/1000 in)
(h) knots to miles per hour (1 knot = 101.5 feet per minute)
(i) degrees of arc per second to revolutions per minute
8. An acre-foot of water will cover an acre of land with a layer of water one foot
deep. How many gallons are in an acre-foot? Use the following factors: 1 acre
= 4840 yd
2 ; and 1 gal = 231 in
3 .
9. Municipal water is sold at 21 cents per 100 cu ft. What is the price per
acre-foot?
10. In the Bohr model of the hydrogen atom, an electron travels in a circular orbit
about the nucleus at approximately 5 x 10
(> miles per hour. How many revolutions per second does the electron make if the radius of the orbit is 2 x 10"
9
inches?
11. A light-year is the distance that light travels in one year at a velocity of
186,000 miles per second. How many miles is it to the galaxy in Andromeda,
which is said to be 650,000 light-years away?
12. A parsec is a unit of measure for interstellar space: it is equal to 3.26 lightyears. How many miles are in one parsec?