A frame of reference is necessary to describe motion and can be an object or group of objects considered stationary. No frame is more correct than another. Speed is calculated by dividing distance by time and can be rearranged to solve for distance or time. Speed is measured in various units like meters/second and miles/hour. Instantaneous, constant, and average speeds describe motion at a moment, without change, or on average over time and distance.

1.  Change in a position of an object
Motioni Unit

2. Essential Questions
 Why is a frame of reference necessary to
describe the motion of objects?
 How is speed calculated?

3.  A frame of reference is an object or a group of
objects that is considered to be stationary.
 An object could be described as moving or as
motionless, depending on the frame of reference
used.
 No frame of reference is more correct than any
other.
 The most common frame of reference is the Earth.
 Look at the cool video now!!!!
Frame of reference

4. Speed
 Rate is any change over time.
 Speed is a rate of change in a position.
 Speed is calculated by dividing distance by time
t
d
s 

5. Algebra Time
 Use your algebra skills to rearrange the
speed equation to solve for distance and
for time.
 d =
 t =

6. Algebra Time
 Use your algebra skills to rearrange the
speed equation to solve for distance and
for time.
 d = st
 t = d/s

7. Unit of Speed
 m/s
 mi/hr
 ft/sec
 cm/century

8. Specific Speeds
 Instantaneous speed is the rate at which an
object is moving at a given moment of time.
 Constant speed- the rate of motion that does
not change.
 Average speed – the total distance traveled
divided by the time it takes to travel that
distance.

9. Reading Assignment
 Enriched: Pages 19-21
 Regular: Pages 332-334