Motion in oneCHAPTER 21. MOTION IN ONE DIMENSION

dimension

21

Introduction ESAGS

This chapter is about how things move along

a straight line or, more scientifically, how

things movein one dimension. This is useful

for learning how to describe the movement

(motion) of cars along a straight road or of

trains along straight railway tracks. There are

three features of motion that we use to de-

scribe exactly how an object moves. They

are:

Traffic often moves along a straight line.

Photograph by warrenski on Flickr.com

FACT

Thejerkis the name

we give to how fast

the acceleration is

changing.

1 .positionwhich tells us about an object’s location ordisplacementwhich tells us

about change of location

2 .speedwhich tells us how fast the object is moving orvelocitywhich tells us how fast

the object is moving and where it is moving to, and

3 .accelerationwhich tells us exactly how fast the object’s speed and velocity are chang-

ing.

See introductory video: ( Video: VPgiq at http://www.everythingscience.co.za)

Reference frame ESAGT

The first thing to focus on when studying motion of an object or person is their position.

The wordpositiondescribes your location (where you are). However, saying that you

arehereorthereis meaningless, you have to use known points (reference points) to help

specify your position.

Physics: Mechanics 387