SIMPLE HARMONIC MOTION Drexel University（简谐运动德雷克塞尔大学）.pdfVIP

SIMPLE HARMONIC MOTION PURPOSE The purpose of this experiment is to investigate one of the fundamental types of motion that exists in nature - simple harmonic motion. The importance of this kind of motion can be appreciated by listing a few examples that include pendulum motion, the oscillating circuit used to tune a radio receiver, and the bobbing motion of a car with worn shock absorbers. Less common, but perhaps more interesting to the physicist are the interatomic vibrations of molecules, the motion of gas molecules propagating a sound wave, and the time behavior of electric and magnetic fields (including light) traveling through space. Probably the simplest form of simple harmonic motion is the oscillation of a mass suspended from a vertical spring. It is this form we will be studying in this lab. We will determine the elastic spring constant K of a spring first and then study small vertical oscillations of a mass suspended from the spring. THEORY How can so many diverse systems exhibit essentially the same kind of motion? The answer lies in the fact that each of these systems obeys the same fundamental mathematical equation. Lets quickly review how this equation comes about in the case of a mass suspended from a spring. The springs you will be using obey Hookes Law, F = - K (x - x ) (1) s o Here, xo is the equilibrium position of the spring and the minus sign indicates that the force exerted by the spring is in the opposite direction to the displacement, (x - x ), of the mass. This