Transcript Speed

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Vocabulary
Speed: the ratio of the distance an object
moves to the amount of time the object
moves
Velocity: the speed and direction an object
is moving, measured relative to a reference
point
Average speed: the total distance traveled
divided by the time it takes to travel that
distance
Instantaneous speed: the rate at which an
object is moving at a given moment
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S8P3. Students will investigate relationship
between force, mass, and the motion of
objects.
a. Determine the relationship between
velocity and acceleration. (DOK 2)
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It is a rate!
What does that
mean?
A change over time.
What is the change?
Change in position,
in other words,
distance.
Standard unit:
meters per second
(m/s)
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Instantaneous –rate
at a given moment
in time
Example:
speedometer in a
car
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Average speed –
rate for the
duration of an
entire trip
This can be
calculated…ready
for the equation?
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v = d/t
v – velocity
d – distance
t – time
What units do we
use?
Try the practice
problems.
1. A train travels 190
km in 3.0 hours and
then 120 km in 2.0
hours.
2. A car travels 85
km from Town A to
Town B, then 45 km
to Town C. The
entire trip took 1.5
hours.
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What makes
velocity different?
It is a vector!
It is essentially
speed (magnitude)
and direction
3 ways to change
velocity:
◦ Change in speed
◦ Change in direction
◦ Change in both
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Velocity is
demonstrated on a
distance vs. time
graph
The slope of the
line demonstrates
speed/velocity
The steeper the
slope, the higher
the speed
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Explain how speed is considered a rate.
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How does velocity differ from speed?
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What shows the speed on a distance-time
graph?