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)
Simple harmonic motion
Two requirements:
1.Force always
points towards
the equilibrium
position
2.It is called the
restoring
force.
(1) F = -kx
(2) No friction
vt
90-θ
θ
ac
Simple Harmonic motion
two important parameters: A and ω
•
•
•
•
•
x = A cos ωt
v = -A ω sin ωt
a = -Aω2 cos ωt
ωT = 2π Î T = 2π/ ω
k
v =±
A2 − x 2
m
(
k For mass on a spring
ω=
m
1 k
m
f =
T = 2π
2π m
k
• Do NOT use the uniformly accelerated
motion equations
)
x = A cos ωt
Simple
Harmonic
Motion
(SHM)
v = -A ω sin ωt
a = -Aω2 cos ωt
Period T
Simple Pendulum
• another example of
simple harmonic
motion
Tension
• The force is the
component of the
weight tangent to the
path of motion
Ft = - m g sin θ
≈ -mg θ (for small θ)
= -mg (s/L)
L
T = 2π
g
Tension
L
T = 2π
g
13. Vibrations and Waves
Found everywhere in the universe and in daily life.
• hearing and vision.
• Ultrasound diagnostics.
Image: Absorption, Transmission,
and Reflection of ultrasound
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