Page 423 - Basic College Mathematics with Early Integers

WEIGHT AND MASS: U.S. AND METRIC
Objectives
5.5 SYSTEMS OF MEASUREMENT
Define U.S. Units of Weight and
Convert from One Unit to Objective Defining and Converting U.S. System
Another.
Units of Weight
Perform Arithmetic Operations
Whenever we talk about how heavy an object is, we are concerned with the object’s
on U.S. Units of Weight.
weight. We discuss weight when we refer to a 12-ounce box of Rice Krispies, a
Define Metric Units of Mass and 15-pound tabby cat, or a barge hauling 24 tons of garbage.
Convert from One Unit to
Another.

Perform Arithmetic Operations
on Metric Units of Mass.

12 ounces
15 pounds
24 tons of garbage

The most common units of weight in the U.S. measurement system are the
ounce, the pound, and the ton. The following is a summary of equivalencies
between units of weight:

U.S. Units of Weight Unit Fractions
16 oz 1 lb
16 ounces 1oz2 = 1 pound 1lb2 = = 1
1 lb 16 oz
2000 lb 1 ton
2000 pounds = 1 ton = = 1
1 ton 2000 lb

Concept Check If you were describing the weight of a fully loaded semitrailer,
which type of unit would you use: ounce, pound, or ton? Why?

Unit fractions that equal 1 are used to convert between units of weight in the
U.S. system. When converting using unit fractions, recall that the numerator of a
unit fraction should contain the units we are converting to and the denominator
should contain the original units.

PRACTICE 1 Example 1 Convert 9000 pounds to tons.
Convert 6500 pounds to tons.
Solution: We multiply 9000 lb by a unit fraction that uses the equality
Answer
2000 pounds = 1 ton.
1 Copyright 2012 Pearson Education, Inc.
1. 3 tons
4
units to convert to 1 ton
Remember, the unit fraction should be or .
Concept Check Answer original units 2000 lb
ton
400