Ch. 11, Vibrations and Waves. A repeated motion, like the pendulum on a clock, is called periodic motion . Another exp is a mass on a spring. At the equilibrium position, the speed is at its maximum. At the equilibrium position, the acceleration is zero.
A repeated motion, like the pendulum on a clock, is called periodic motion.
In simple harmonic motion (SHM), restoring force is proportional to displacement.
The restoring force on a pendulum is a COMPONENT of the bob’s weight.
As long as a pendulum stays within an angle of about 15 degrees, it is a very good example of SHM.
Page 374, Figure 5, Gravitational Potential increases as a pendulum’s displacement increases.
Most waves are called Mechanical Waves. They need a medium to travel through.
Transverse waves The particles vibrate perpendicularly to the direction the wave is traveling.
Longitudinal Wave The particles vibrate PARALLEL to the wave’s motion.
Frequency = number of complete waves that pass a certain point per second.
The combination of two overlapping waves is called superposition.
Constructive interference: Two or more waves on the same side of the equilibrium position combine and form a bigger wave.
Destructive interference is the superposition of two or more waves that are on opposite sides of equilibrium. A smaller wave results.
Reflection: a wave is reflected at a free end; a wave is reflected AND inverted at a fixed end.
Standing Wave: occurs when two equivalent waves interact in opposite directions.