# Motion

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14 Νοε 2013 (πριν από 4 χρόνια και 7 μήνες)

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Motion

Motion

Motion
-

the change in the position of an
object with respect to time and its
reference point

Motion is RELATIVE

Reference point/
frame of reference
:
a
point/object that is not moving

Reference Point and Relative Motion

Example:

-
If you are sitting on a train looking at your
neighbor, neither of you seem to be moving

-
If you look out the window at people standing
on the side, they seem to be moving
backwards

-
If the people on the side are looking at you,
you seem to be moving forward

Describing Motion

Distance
-

the length between two points

Units: meters, kilometers, etc.

Time

Speed

Speed
-

is the distance traveled per unit
of time

Units: m/s, km/s, etc.

S= speed

D = distance

t= time

Solve for other variables
:

D
= s*t

t= D/s

Formula
:

S
= D/t

Average Speed

The total distance divided by the total
time

Instantaneous Speed

The speed at any given instant

You must always show your
work and
units!!

ALWAYS METRICS

without units!

Let’s try one!

Calculate the speed of a dog running through a field if
he is covering 23.7 meters in 54 seconds.

Given
:

Formula:

Find
:

Work
Space
:

If a cross country runner covers a distance of 347
meters in 134 seconds what is her speed?

Given:

Formula:

Find:

Work Space:

Velocity

Velocity
-

The speed and direction an object is
moving in

Units: speed and a direction

Example: The car’s velocity is 60 km/hr EAST

Try This:

Calculate the velocity of a dog running north through a
field if he is covering 23.7 meters in 54 seconds.

Given:

Formula:

Find:

Work Space: