HITT RF Remote Login Procedure:
The radio channel number for this room is “07” (zero, seven).
It is STRONGLY recommended to login your remote for every class just
to be sure it is on the correct radio channel and working before class.
1.
2.
3.
4.
PRESS AND HOLD THE DOWN ARROW KEY until the
GREEN light on the remote turns RED.
PRESS THE “0” KEY and you will see the RED light flash
GREEN.
PRESS THE “7” KEY and you will see the RED light flash
GREEN.
PRESS AND RELEASE THE DOWN ARROW KEY again
and you will see the red light search for the receiver, if it
BLINKS GREEN MULTIPLE TIMES you are logged in.
Phy 2053 Announcements
Final Exam
–
April 24 Saturday, 8 – 10 pm
•
Please get there at least 10 minutes early
–
Covers all material taught in this course.
–
Room assignments
•
Last name
Room
A–G
Chemistry Lab Bldg C130
H – LE
Little Hall 101
LF – RI
Pugh 170
RJ – Z
Weil 270
–
You will be allowed one handwritten formula sheet (both sides)
–
Sample exam from last year posted on website.
Phy 2053 Announcements
Make-up Exam
–
To take the make-up, you must have obtained permission from one
of the instructors (Profs. Acosta, Chan or Hirschfeld)
–
April 21 Wednesday, 6:15 – 8:10 pm
–
Location: NPB 1101
–
Covers all material taught in this course.
–
You will be allowed one handwritten formula sheet (both sides)
Prof. Hirschfeld is out of town on a business trip.
Prof. Chan holds regular office hours (Tue 5th period, Thu 4th period)
Waves: Chapter 13.4-13.7
Transverse wave
Wave velocity
Each part of spring moves
⊥ to wave velocity
λ
X direction (space/not time)
Longitudinal or compression wave
λ
λ = wavelength
Wave velocity
Simple harmonic motion
y
x
Waves
Wave motion-Wave velocity c
c
ct
c = λ/T = λƒ
Always true:
Light-transverse
Sound-longitudinal
Any wave
Waves need a medium-Except light
λ
Chapter 14
Tuning Forks produce single frequency sound
• As the tuning fork vibrates, a succession of
compressions and rarefactions spread out
from the fork
• A sinusoidal curve can be used to represent
the longitudinal wave
– Crests correspond to compressions and
troughs to rarefactions
Categories of Sound Waves
• Audible waves
– human hearing:
Normally between 20 Hz to 20,000 Hz
• Infrasonic waves
– Frequencies are below the audible rangeEarthquakes or car stereos
• Ultrasonic waves
– Frequencies are above the audible range
Dog whistles
Wavefronts
Planar wave front
Distance between wavefronts = λ
spherical wave front
Speed of Sound
Solid Rod
Y ¾Y is the Young’s Modulus of the
v=
ρ material
¾ρ is the density of the material
Liquid
v =
B »B is the Bulk Modulus of the liquid
ρ »ρ is the density of the liquid
In General
elastic property
v=
inertial property
Doppler Effect-Source in Motion
• As the source moves
toward the observer (A),
the wavelength appears
shorter and the
frequency increases:
• As the source moves
away from the observer
(B), the wavelength
appears longer and the
frequency appears to be
lower
⎛ v ⎞
ƒo = ƒ s ⎜
⎟
⎝ v − vs ⎠
Doppler Effect -Observer moving-Source stationary
• Goes toward source
• Encounters more wave
fronts per second-closer
together
• The frequency heard is
increased
• Goes away from source
• The observer detects
fewer wave fronts per
second-farther apart
• The frequency sounds
lower
⎛ v + vo ⎞
ƒo = ƒ s ⎜
⎟
v
⎝
⎠
Doppler Effect-General Case
⎛ v + vo ⎞
ƒo = ƒ s ⎜
⎟
v
⎝
⎠
⎛ v ⎞
ƒo = ƒ s ⎜
⎟
⎝ v − vs ⎠
• Use positive values of vo and vs if the motion is
toward each other--Frequency appears higher
• Use negative values of vo and vs if the motion is
away from each other--Frequency appears lower
• Both the source and the observer could be
moving
⎛ v + vo ⎞
ƒo = ƒ s ⎜
⎟
⎝ v − vs ⎠
Combine the two equations
Speed of Sound in Air
m⎞
T
⎛
v = ⎜ 331 ⎟
s ⎠ 273 K
⎝
T is absolute
temperature in Kelvin
= °C + 273