Module 7—Oscillatory Motion
Lesson Summary
In this lesson you investigated the following questions:
- What is oscillatory motion?
- What is simple harmonic motion?
- What is the equation for the period of a weighted spring?
- How is simple harmonic motion related to circular motion?
Oscillatory motion is motion in which the period of each cycle is constant.
Simple harmonic motion is a case of oscillatory motion where the restoring force is proportional to the displacement of the mass relative to the equilibrium position. The displacement and force are always in opposite directions.
The period of a weighted spring is the time required to complete one cycle. It is defined by the spring constant and the mass of the weight attached to the spring. Mathematically, the relationship is expressed by
The period for simple harmonic motion can be the same as that for circular motion. The radius of the circular motion is identical to the amplitude of simple harmonic motion.
Lesson Glossary
equilibrium position: the position where the resultant of all forces acting is zero
oscillate: to move back and forth at a constant rate
radian: a unit used to measure angles that is calculated as arc length divided by radius
restoring force: a force that causes an object to return to an equilibrium position
simple harmonic motion: a repeating motion about a central equilibrium point caused by restoring forces
spring constant: a measure of the stiffness or strength of a spring (the k in Hooke’s law)