When solving a
problem, you would only use
2 of the ratios at a time.
Wave speed
f
v
Wave speed = frequency
wavelength
True for any wave.
Speed of sound
in air
T
v
C
s
m
s
m
sound
/
6
.
0
331
Speed of sound = 331 + 0.6
air temperature
Temperature must be in ºC.
Echolocation
t
v
D
2
1
Distance to object = ½
wave
speed
elapsed time
The ½ is there because the
waves travel from the source
to the object and then bounce
off of the object & return to
the source.
Wavelength
n
L
Wavelength = total length /
number of waves
True for any wave.
Frequency
t
n
f
Frequency = number of waves /
elapsed time
True for any wave.
Period
n
t
T
Period = elapsed time / number
of waves
True for any wave.
Optic formula
i
o
d
d
f
1
1
1
f
is focal length
d
o
is object distance
d
i
is image distance
Object distance is always
positive.
This formula applies
to both lenses & mirrors.
Theoretical
magnification
o
i
d
d
M
Theoretical magnification =
negative image distance / object
distance
Object distance & height are
always positive.
For the HW,
assume the theoretical
magnification & the actual
magnification equal each
other.
In lab, they will most
likely not equal each other
due to measurement errors for
the distances & heights.
Measured
magnification
o
i
h
h
M
Measured magnification = image
height / object height

Appendix

Review for Graph Final
Use the graph below to answer the following
questions.
1.
When does the moped have positive position?
2.
When does the moped have negative position?
3.
When is the moped at rest?
4.
When is the moped moving with positive
velocity?
5.
When is the moped moving with negative
velocity?
6.
What is the moped’s velocity at t = 5 h?
7.
What is the moped’s velocity at t = 7.5 h?
8.
What is the moped’s velocity at t = 9 h?
9.
What is the total distance covered by the
moped?
10.
What is the total displacement of the moped?
Use the graph below to answer the following
questions.
11.
When does the
car’s
velocity equal zero?
12.
When is the car’s velocity
positive?
13.
When is the car
’s
velocity negative?
14.
What is the car’s acceleration at t=1 s?
15.
What is the car’s acceleration at t=2.5 s?
16.
What
is the car’s acceleration at t=4 s?
17.
What is the car’s acceleration at t=6.5 s?
18.
What is the car’s acceleration at t=9 s?
19.
When is the car speeding up?
20.
When is the car slowing down?
21.
What is the maximum speed of the car?
22.
When does the car have constant velocity?
-40
-20
0
20
40
0
2
4
6
8
10
Position (mi)
Time (h)
Moped Position vs. Time
-4
-2
0
2
4
0
2
4
6
8
10
Velocity (m/s)
Time (s)
Car Velocity vs. Time

Read the following paragraph and then use the graph to answer
the following questions.
A mysterious substance is cooled for 90 minutes.
During
that time the substance went from gas to liquid to solid.
23.
Why is the temperature of the substance not
changing at t = 60 min?
24.
At what temperature did freezing occur?