Transcript 12.2 Speed

Motion and Force
• Chapter Twelve: Distance, Time, and Speed
• Chapter Thirteen: Forces
• Chapter Fourteen: Force and Motion
Chapter Twelve: Distance, Time, and
Speed
• 12.1 Distance, Direction, and Position
• 12.2 Speed
• 12.3 Graphs of Motion
Investigation 12A
Distance, Time, and Speed
• How do scientists describe motion?
12.2 Speed
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Speed is the most common measurement
used to describe the motion of objects.
Once you know an object’s speed, you
can figure out how far it can go in a certain
amount of time.
You can also predict how long it will take
to get somewhere.
12.2 Speed
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The speed of a bicycle is the distance it
travels divided by the time it takes.
12.2 Velocity
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Speed with direction is called velocity.
12.2 Constant Velocity
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A plane with a constant
velocity of 600 km/h
west moves in a straight
line. (Its speed and
direction remain the
same.)
A car going around a
bend at a constant 30
mph has a constant
speed, but its velocity is
not constant. (Note the
change in direction.)
12.2 Average Speed
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The speed found
by dividing the total
distance by the
total time is the
average speed.
12.2 Relationships between distance,
speed and time
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An equation can be used to calculate speed,
distance, or time if two of the three values are
known.
Activity
How Fast are You?
• Speed is how fast something
moves in relation to a
reference point without regard
to the direction.
• In this activity you and a
partner will each calculate your
average speed in different
units.