Course Web Page for Phys1061

Fall 2005

 

Quizzes   Phys 1061, Fall 2005

 

Look for solutions and discussions of quizzes right here.

 

Thursday, November 17, 2005: solution for quiz 9

 

Friday, November 11, 2005:solution for quiz 8

Try the following experiment: Familiarize yourself with the Helmholtz resonance frequency of a softdrink bottle of your choice. Then hold the bottom of the bottle against your ear. That works best in a place where there is some white noise, like wind blowing or, a fan, or some other source of broadband noise. You will hear the parts of the noise which resonate with the Helmholtz resonator enhanced. This was actually used in order to determine the frequency composition of sounds, before we had electronic means of doing so.

 

Tuesday, November 08, 2005: solution for quiz 7

 

Wednesday, October 12, 2005: Solution for Quiz 6

In grading your Quizzes:

Sound in air moves at about 300 m/s, as many of you correctly recognized. However, there are other objects which can move at speeds of this magnitude, or even faster:

Air planes, rocket cars, the end of a whip ….

Anything that creates a sonic boom is moving at more than the speed of sound.

That also should answer why I did not give points for the suggestion that cars move at this speed: seldom do we hear a sonic boom from a traveling car, with the exception of experimental rocket cars for breaking speed records in the Nevada desert. Below is a picture of an F18 breaking through the sound barrier, meaning just becoming faster than the speed of sound.

 

 

Thursday, October 06, 2005: Solution for Quiz 5

 

Wednesday, September 28, 2005: solution for quiz 4

Remarks to your answers:

  1. The force is directed downward inplaces where the spring is compressed. This will be the case anytime the mass is located above the equilibrium line.
  2. The amplitude or energy is decreasing for a damped harmonic oscillator. Some of you answered speed and force. The problem with these answers is, that both, speed and force are changing throughout the oscillation. What would it mean for them to decrease, if they are changing all the time? You need to qualify this as maximum speed or maximum force for it to become a correct answer, since these characterize basically the amplitude in speed and force. Those will decrease in a damped harmonic motion.
  3. The frequency of a harmonic oscillator is not dependent on the amplitude. That is one very important characteristic of the harmonic oscillator. Some of you answered mass. While this is true for a particular type of oscillator (the pendulum), it certainly is not true for all harmonic oscillators. The frequency of a mass-spring system is explicitely dependent on the mass.

 

 

Wednesday, September 14, 2005: Solution for Quiz 3

 

Friday, September 09, 2005: Solution for Quiz 2

 

Friday, September 02, 2005: solution for Quiz 1. If you have no calculator with you, please write down the procedure or equation with numbers you would follow. Bring your calculator to class.

Some of you answered “pitch” as a difference for note C played on organ and harp. Note C is a descriptor for pitch. If both instruments play the same note, they play in the same pitch (ideally). Differences are timbre, loudness and duration.

 

 

 

 

 

 

 

Page last modified: 11/17/2005 2:11 PM

Maintained by Sylke Boyd, sboyd@umn.edu

University of Minnesota-Morris, Division of Science and Mathematics

The views and opinions expressed in this page are strictly those of the page author. The contents of this page have not been reviewed or approved by the University of Minnesota.