Making measurements
I make the following time measurements for a falling ball. What is the average?
1.2 s
1.6 s
1.9 s
0.7 s
1.3 s
1.4 s
1.35 s
Referencing the graph from slide 10 - approximate the amplitude
~11 Pa
If a wave oscillates with a frequency of 105 Hz, determine the period.
Describe what happens to the period is the frequency is decreased to 10.5 Hz.
0.0095 sec
The period will increase by 10 to 0.095 sec
Describe a transverse wave and give at least one example of one
A wave where the displacement of the particles are perpendicular to the direction the wave is traveling.
Ex: A guitar string
I make the following time measurements for a falling ball. What is the uncertainty?
1.2 s
1.6 s
1.9 s
0.7 s
1.3 s
1.4 s
+/- 0.65
Referencing the graph on Slide 9 - determine the amplitude
2.25 m
Your friend stands at the opposite end to you on an American football field (110 m). You start your stopwatch when you see him clap and stop it when you hear the sound. Your stopwatch reads 0.32 seconds.
What is the approximate speed that the wave traveled through the air?
~343 m/s
Describe a longitudinal wave and give at least one example.
A wave where the displacement of the particles are parallel to the direction the wave is traveling.
Ex: A sound wave
Describe in words what it means for a period measurement to be 5 +/- 0.5 s
If you measure the period again, the most likely measurement you will make is 5 seconds and it will likely fall within the range 4.5 and 5.5 seconds.
Referencing the graph on Slide 9 - Determine the period and frequency of the wave
7 seconds
0.14 Hz
A pulse on a 5 meter long string takes 2.7 seconds to travel from one end to the other. Assuming you oscillate that string at 2 Hz, calculate the wavelength.
0.9 m
Describe when and why we use displacement vs. pressure on the y-axis
Displacement: transverse wave - the particles are being displaced up and down
Pressure: longitudinal sound wave - the particles are bunching up, creating more pressure (like a balloon), and spreading apart creating less pressure.
Suppose you take 50 time measurements of an SUV and a sports car driving 60 miles.
You find the time it takes for an SUV to drive 1 mile to be 60 +/ 7 seconds and the time it takes for the sports car to drive it to be 45 +/- 9 seconds.
Can you definitively say that the sports car will always drive faster (i.e. take less time to drive 60 miles)?
The sports car has a maximum time of 54 seconds whereas the minimum time for the van is 53 seconds. Therefore it can't be concluded that the sports car will always drive faster.
Referencing the graph on slide 10.
Using this graph, calculate the frequency of oscillation assuming this is a sound wave traveling through air (v=343 m/s)
10.09 Hz
To image small organs in the body, ultrasound needs to have really small wavelengths (0.0015 m). If the ultrasound waves are traveling through tissue (v=1500 m/s), calculate the necessary frequency of the ultrasound wave as it passes through you.
If humans were made of air (v=343 m/s) instead, would you need a larger are smaller frequency?
1,000,000 Hz
Smaller (~228,000 Hz)
Describe what musical concepts amplitude and frequency relate to.
Amplitude: Directly relates to loudness
Frequency: Directly relates to the pitch