SMDEP Physics

1
SMDEP Physics

• Oscillations, Waves
• Any trumpet players in the house? Please see me
  after class today.
• Webpage updated http//www.astro.yale.edu/krines
  /smdep

2
Quiz Results

• Pre-quiz and Post-quiz to measure change
• Pre-quiz mean 8.6 (max24)
• Post-quiz mean 15.7 (max29)
• This change is larger than most semester-long,
  lecture-based courses
• You all did it in 11 days!
• Individual Pre/Post scores available at end of
  class

3
Ch 15, 2 AM radio wavelength?

• 200-550 km
• 200-550 m
• 20-55 m
• 2-5.5 mm
• Other
• Didnt finish

4
Ch 15, 2b FM radio wavelength?

• 2.8-3.4 km
• 0.29-0.36 m
• 28-34 m
• 2.8-3.4 m
• Other
• Didnt finish

5
Ch 15, 12 ratio of amplitudes?

• 2
• 21/2
• 4
• 81/2
• Other
• Didnt finish

6
A mass attached to a spring oscillates back and
forth as indicated in the position vs time graph
below. At point P the mass has
x

• Positive velocity and positive acceleration
• Positive velocity and negative acceleration
• Positive velocity and zero acceleration
• Negative velocity and positive acceleration
• Negative velocity and negative acceleration

P
t
7
The picture below is a top view of ripple waves
made by a water bug moving on the surface of a
lake. From the wave pattern, we can see that the
bug has been moving

• Continuously to the left
• Continuously to the right
• Back and forth, first right then left
• Back and forth, first left then right
• In a circle

8
If the frequency of a wave in a medium is
increased, how does the velocity of the wave
change?

• It increases
• It decreases
• It stays the same