Waves_KostmanL

__** Waves **__ toc Lauren Kostman

Lesson 0: Vibrations
__Lesson a: Vibrational Motion__ What causes things to vibrate? - Objects have resting positions (equilibrium position); when positioned at it's equilibrium position, the object is at equilibrium (has balanced forces) - When a force is applied to the object, it can be displaced from its equilibrium position - The force disturbs the equilibrium and causes the object to vibrate - Some objects experience damping (when a vibrating object loses energy over time, ex: bobble head) What is the restoring force? - It is the force that acts upon the vibrating object to move it back to its original equilibrium position __Lesson b: Properties of Periodic Motion__ What is periodic motion? - It is a motion that is regular and repeating (most objects vibrate this way) - The graph is that of a sin function - PERIOD= the time for the mass to complete a cycle; sec/cycle - AMPLITUDE= the maximum displacement of the mass above or below the resting position - FREQUENCY= the number of complete cycles occurring per period of time; cycle/sec __Lesson c: Pendulum Motion__ What is pendulum motion? - An object must experience a resotring force to vibrate - Hanging masses that swing back and forth move as a pendulum What are the forces acting on a pendulum? - The force of gravity is always directed downward (its magnitude never changes; 9.8) - The tension force is always directed towards the pivot (its magnitude varies over the course of the vibration) - Graph --> sin function

__Lesson d: Motion of a Mass on a Spring__ What is the motion of a mass on a spring? - Use Hooke's Law (force= k*x) - Graph--> sin function - Period of mass on a spring:

Lesson 1: The Nature of a Wave
__Lesson a: Waves and Wavelike Motion__ Describe waves and their motion. - The 2 most common types of waves are sound waves and light waves - The motion of a pendulum, the motion of a mass suspended by a spring, and the motion of a child on a swing can be thought of as wavelike - Waves can move together as a front in a straight-line direrction - Or they can be circular that originate from a point where the disturbance occurred and travel in all directions __Lesson b: What is a Wave?__ What is a wave? - It's a repeating and periodic disturbance that travels though a medium from one location to another - A pulse is a single disturbance moving through a medium from one location to another - A medium is a substance or material that carries a wave - Waves transport energy and not matter __Lesson c: Categories of Wave__s What types of waves are there? - Transverse wave: one in which particular particles of the mdium move in a direction perpendicular to the direction that the wave moves - Longitudinal wave: one in which particles of the medium move in a direction parallel to the direction that the wave moves - Surface wave: one in which particles of the medium undergo a circular motion - Electromagnetic wave: one that is capable of transmitting its energy through a vacuum - Mechanical wave: one that is NOT capable of transmitting its energy through a vacuum (ex: a sound wave)

May 7, 2012

Lesson 4: Standing Waves
__a.) Traveling Waves vs. Standing Waves__ What is the difference between a traveling and a standing wave? - Mechanical wave= a disturbance created by a vibrating object that then goes through a medium from one point to another, transporting energy as it moves - Traveling wave= when a wave is not confined to a given space along the medium (ex: ocean waves) - Standing wave= when a wave is confined to a given space in a medium and still produces a regular wave pattern; it's characterized by points appear to be standing still __b.) Formation of Standing Waves__ Describe the formation of standing waves. - Standing wave pattern= a vibrational pattern created within a medium when the vibrational frequency of the source causes reflected waves from one end of the medium to interfere with incident waves from the source - Harmonics= these frequencies - 2 pulses can interfere/ pass through each other __c.) Nodes and Anti-nodes__ What are nodes and anti- nodes? - Nodes (N)= points along the medium that have no displacment - Anti-Noes (AN)= points along the medium that vibrate back and forth between points of large positive and negative displacements __d.) Harmonics and Patterns__ Describe harmonic wave patterns. - __e.) Mathematics of Standing Waves__ What is the mathematics of standing waves? -