| Often we say,
"the car is moving at 60 km/h" or "he's walking at 1 m/s" these
are speeds. When we say, "the car is moving at 60 km/h due east"
this quantity becomes a vector instead of a scalar as
mentioned before. 60 km/h due east has a specifically name, called "velocity". Here, we will take a look at constant speed, average
speed and instantaneous speed. |
Average speed = |
distance traveled |
| time elapsed |
|
The rocket travels a distance measured along
its actual path through space. After a time, t, having gone a distance, l,
its average speed is Vav = l/t. |
|
Constant speed: |
distance = constant speed x time |
| An object traveling at a constant speed covers
equal distances in equal intervals of time. |
 |
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| Instantaneous
speed: |
The central notion
here is that  l will become infinitely small as t becomes infinitesimally
small, and yet their ratio, |
 |
, will approach a finite limiting value.
This limiting value |
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| approached by |
|
as t -->
0 (that is, as t gets |
|
| infinitesimally
small) is called the instantaneous speed, v. Mathematically that's
written as: |
|
 |
To find the instantaneous speed of the bee at
point P, determine the average speed over a tiny interval
straddling P. Then shrink l until Vav
remains constant at the instantaneous speed, v. |
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l 
