Physics 4AL
Lab for Science and
Engineering Mechanics
Experiment:
Lab Section:
Name:
UID:
Date:
TA:
Partner:
Lab Station:
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Introduction/Purpose:
The objective of this lab is to observe the properties of vibrating strings, and is
conducted in three parts. The first part of the lab allowed us to calculate velocity in two
ways, experimentally and theoretically. The second part of the lab used this data to
determine the fundamental frequency and overtones of the system. Lastly, the third part
was designed to see how holding the string at the midpoint would affect the system.
Theory/Equations/Procedure:
The theory behind this lab not very complicated. The string is first weighed, and
then the length is measured. The string is then placed into the jig, in which it is held down
at one end by a clip, runs over a pulley at the other end, and has photogate laser towards
the pulley end to measure movement. On the opposite side of the pulley hangs a mass,
and right next to the clip is a motor that drives the oscillations. For the first part, we need
to calculate the velocity of the string. For this, we have the motor produce a saw tooth
oscillation in the string, and use the formula V = (2*Length)/(Change in time) to
determine the velocity experimentally. We then calculate the velocity theoretically by
using the formula V = SQRT(Force of tension/mass per unit length) = SQRT(Ft/mu). It is
important to note that the mass hanging from the pulley (as well as the string between the
mass and the pulley) serves to create the tension force used in the above equation. Once
the velocity is calculated, we can use it to calculate the fundamental frequency of the
system by using the equation F1 = Velocity/Twice the length, so… F1 = V/2L. Knowing
the fundamental frequency, we can then calculate the next overtones by using the
equation Fn = n*F1. We then use the motor to produce these frequencies, and see how
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '08
 SLATER
 Physics, mechanics, Harmonic Series, Vibrating string, Fundamental frequency, Musical tuning

Click to edit the document details