MOTION.notebook
October 10, 2013
Notes
September , 2013
How do you know when something is in motion??
Motion: The state in which one object‛s distance from
another is changing based on a reference point. An object is
only in motion when its distance is changing.
Reference Point: A place or object used for comparison to
determine if something is in motion.
Distance vs. Displacement
Distance: the total length between two points
traveled.
Vector: a physical quantity that is specified
by a size and direction.
Ex.
Displacement: a vector that refers to "how far
out of place an object is"; how far an object is
from its starting position.
Ex.
Walk 1 mile to the movies and continue to walk
1/2 mile for ice cream in the same direction
(east).
Distance = ___________
Displacement = ___________
After ice cream you walk 1 mile to your friends
house (west).
Distance = ___________
Dispacement = ___________
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MOTION.notebook
October 10, 2013
Reference Points
Example...
How fast are you moving sitting at your
desk relative to the floor?
Relative to the Sun?
Sitting in your
car at a stop
light... next to
a big vehicle...
Being on a
cruise ship...
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Speed - a measure of an object's distance
covered over an amount of time.
**FORMULA**
Speed = Distance ÷ Time
**UNITS**
m/s
<-- Used most often
(Whatever the distance
unit is / what the time unit is)
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MOTION.notebook
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Distance
Speed
Time
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Notes
October 10, 2013
October
2013
Velocity: The speed of an object and the direction of its
motion. (Velocity is a vector)
Ex. The hurricane is moving at a speed of 10 km/h East.
Acceleration: The rate at which speed/velocity changes.
• Increasing Speed- (Positive Acceleration)
A car moving from a stopped position
• Decreasing Speed (Negative Acceleration OR Deceleration)
A ball decelerates when rolling to a stop, a
jetlanding on a runway
• Changing Direction
A car moving around a curve at constant speed (still
accelerating because the car is changing direction)
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Acceleration Formula
Acceleration = Final Speed - Beginning Speed
Time
Shorter Version -->
Units = m/s2
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While drag racing out
of our school parking
lot, I time myself at
a speed of 40 m/s 7
seconds after
starting.
What was my
acceleration?
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