DEPARTMENT OF APPLIED PHYSICS
Physical Measurement 201
DRIVEN HARMONIC OSCILLATOR
Abstract
The purpose of this experiment is to investigate the various aspects of harmonic motion using a Driven Harmonic Motion Analyser (DHMA). The aspects that are investigated in this experiment is the spring constant k of two springs, the resonant frequency, the damping factor, and the relationship between phase and resonant frequency. The value of k of the first string by calculating the mean is (12.51 ± 0.001) N/m and the value of k by using linear regression is (12.7 ± 0.3) N/m. The value of k of the second string by calculating the mean is (9.79 ± 0.001) N/m and the value of k calculated using linear regression is (9.1 ± 0.5) N/m. The damping coefficient caused by magnet is (0.021 ± 0.001) Ns/m. The value of resonant frequency using spring 2 with no mass added is (2.1 ± 0.1) Hz, this value is obtained from looking at the maximum amplitude, the other values obtained from calculation and looking at the phase are 2.05 Hz and (2.5 ± 0.1) Hz.
Experiment Conducted:
27th April 2004
AIM
General:
- Investigate various aspects of harmonic motion using a driven harmonic motion analyser
Specific: - Measure the spring constant k for two springs - Measure the resonant frequency - Investigate the effect of damping on the period of the oscillation, and to determine the damping coefficient b - To investigate the relationship between the phase and resonant frequency.
EQUIPMENT - Driven harmonic motion analyser - Computer interface - Additional masses (0.01 kg each) - Magnetic damping unit - 2 Springs - Meter ruler
INTRODUCTION
Consider a mass attached to a spring, damped and oscillated with external force as seen on the following diagram:
[pic]
Figure 1. Mass attached to a spring with constant k and it is damped with a
References: PASCO scientific, 1986, Instruction Manual and Experiment Guide for the PASCO Scientific Model ME-9210A, Roseville, CA, USA Pain, H.J. 2000, 5th edition, The Physics of Vibrations and Waves, John Wiley & Sons Limited, Chichester, UK