10 Unit 1: Motion and Forces

Describing a PositionYou might describe the position of a city based on the location ofanother city. A location to which you compare other locations is calleda You can describe where Santiago, Chile, is from thereference point of the city Brasília, Brazil, by saying that Santiago isabout 3000 kilometers (1860 mi) southwest of Brasília.

You can also describe a position using a method that is similar todescribing where a point on a graph is located. For example, in thelongitude and latitude system, locations are given by two numbers—longitude and latitude. Longitude describes how many degrees east orwest a location is from the prime meridian, an imaginary line runningnorth-south through Greenwich, England. Latitude describes how manydegrees north or south a location is from the equator, the imaginarycircle that separates the northern and southern hemispheres. Having astandard way of describing location, such as longitude and latitude,makes it easier for people to compare locations.

reference point.

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Learn more about howpeople find and describeposition.

There are several different ways to describe a position. The way you choose may depend on your reference point.

Describing Position

Brasília

Santiago

CHILE

B R A Z I L

P A C I F I CO C E A N

A T L A N T I CO C E A N

N

S

EW

0 500 1000 kilometers

0 500 1000 miles

Reference Point: Brasília1

120° W 80° W100° W 40° W 20° W60° W 40° E20° E0°

0°

20° N

40° N

60° N

20° S

40° S

Santiago (33° S, 71° W)

0°

lon

gitu

de

0° latitudeequatorequator

prim

e merid

ian

Reference Point: 0° longitude, 0° latitude2

Compare and contrast the two ways of describing the location of Santiago as shown here.

To describe where Santiago is, using Brasília as a reference point, you would need to know how farSantiago is from Brasília and in what direction it is.

In the longitude and latitude system, a location isdescribed by how many degrees north or south it isfrom the equator and how many degrees east or west it is from the prime meridian.

3000 km southwest

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