Motion
Speed, Velocity,
and Acceleration
Frames of Reference



The object or point from which
movement is determined
Movement is relative to an
object that appears stationary
Earth is the most common
frame of reference
Questions
 What
is the frame of
reference for the sunset?
 What is a frame of
reference?
 What is the most common
frame of reference?
Question
 When
can you
determine how fast you
are going in a jet
plane?
Motion
Motion is a change in
position relative to a frame
of reference
 Speed is the distance
traveled in a given amount
of time
 Speed=distance

time

Speed
 The
units for speed:
 meters/second (m/sec)
 kilometers/hour (km/hr)
 Speed that does not
change is constant speed
Average speed
Total distance divided by
the total time
 Formula:
 Total distance
total time

Velocity
Speed in a given direction
 Velocities in the same
direction combine by adding
 Velocities in different
directions combine by
subtracting

Interesting fact
 Rockets
are launched
in the same direction
of the earth’s rotation
to get an extra boost of
1800 km/hr to its speed
Questions
 What is motion?
 What is speed? How is
it calculated?
 What is average
speed?
Questions
 How
is velocity different
from speed?
 Which two factors
determine an object’s
velocity?
Acceleration
 The
change in velocity
 Acceleration is measured
in m/sec/sec or m/sec2
 Formula is:
 (final velocity - original
velocity)/time
Deceleration vs. Acceleration
A
decrease in velocity is
negative acceleration
(“deceleration”)
A
distance-time graph for
acceleration is always a
curve
Centripetal Acceleration
 Acceleration
directed
toward the center of
circular path
Questions
 What
is acceleration?
 What is the shape of a
distance-time graph for
acceleration?
 What is centripetal
acceleration?
Momentum
 Momentum is equal to
the mass of an object
times its velocity
 momentum= mass x
velocity
Conserving Momentum
 The
law of
conservation of
momentum states that
the total momentum is
NOT lost, only
transferred
Questions
What is momentum?
 What happens to momentum
as the mass of a moving
object increases?
 What is the formula for
momentum?
 What is the law of
conservation of momentum?
