Periodic Motion and Waves

Waves & Vibrations - Basics

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Wave Vocab

• Periodic motion - any motion that repeats itself over and over

• Wave - a disturbance that carries energy as it moves (or propagates).

• Oscillation - repeated back and forth motion at a regular speed

• Period - the time required to complete one wave

• Frequency - the number of oscillations per second

• Hertz - the unit for frequency

• Amplitude - the maximum displacement from equilibrium

Multiple Choice

What is the length between one point of a wave to the same point on the next wave called?

• Wavelength
• Trough
• Amplitude
• Crest

Multiple Choice

The distance from the equilibrium position to the crest or trough is called the what? Also known as the height of a wave.

• Trough

• Wavelength

• Amplitude

• Crest

Multiple Choice

The distance from the equilibrium position to the crest or trough is called the what? Also known as the height of a wave.

• Trough

• Wavelength

• Amplitude

• Crest

Vocab (continued)

• Crest - the highest point in a wave

• Trough - the lowest point in a wave

• Compression - points on a wave that a pushed close together

• Rarefaction - points on a wave that spread apart

• Transverse Wave- wave in which the particles oscillate at right angles to the direction the wave travels

• Longitudinal Wave- wave in which the particles oscillate parallel to the direction of propagation

• Phase - the position of a point in time (an instant) on a waveform cycle

Vocab (continued)

• Simple harmonic motion - periodic motion that occurs when the restoring force an object is proportional to the displacement from equilibrium

• Hooke’s Law - the law that states that the force exerted by an ideal spring is spring proportional to the distance by which it is stretched or compressed.

• Restoring force - the force that acts to bring an object back to equilibrium

• Simple Pendulum - an object (or mass) suspended by a light rope or rod

• Wave Speed - the rate at which a wave travels (m/s)

Multiple Choice

Define restoring force

• a force that acts to bring an object back to equilibrium

• the position of a point in time (an instant) on a waveform cycle

• the frequency at which an object oscillates by itself

• the phenomenon where an object is driven (forced to vibrate) at its natural frequency

Multiple Choice

Define Hooke's Law

• periodic motion that occurs when the force pushing or pulling an object toward equilibrium is proportional to the displacement from equilibrium

• repeated back and forth motion at a regular speed

• the force exerted by an ideal spring is spring proportional to the distance by which it is stretched or compressed.

• the phenomenon where an object is driven (forced to vibrate) at its natural frequency

Vocab Continued

• Natural Frequency - the frequency at which an object vibrates normally (naturally)

• Resonance - the phenomenon where an object is driven (forced to vibrate) at its natural frequency

• Harmonic - a multiple of an object's natural frequency

• Medium- the matter through which a wave travels

• Mechanical Wave- waves that travel through matter

Multiple Choice

Define Resonance

• periodic motion that occurs when the force pushing or pulling an object toward equilibrium is proportional to the displacement from equilibrium

• repeated back and forth motion at a regular speed

• the force exerted by an ideal spring is spring proportional to the distance by which it is stretched or compressed.

• the phenomenon where an object is driven (forced to vibrate) at its natural frequency

Multiple Choice

Waves transfer ________, but they do not transfer _________.

• Matter, Energy
• Energy, Matter

Waves & Oscillations

• Waves carry energy as they travel, not matter

• EX - the sun transmits light waves to Earth but none of the sun travels with it.

• Oscillations occur when an object is moving back and forth.

• Oscillations have wave-like motion

• Oscillations and waves have a frequncy, period, wave speed, etc.

Waves

Multiple Choice

 A wave has frequency of 5 Hz and a speed of 25 m/s. What is the wavelength of the wave?

• 25 m
• 125 m
• 5 m
• 25 m/s

Multiple Choice

A tennis coach paces back and forth along the sideline 10 times in 2 minutes. The frequency of her pacing is 

• 5 Hz
• 5 s
• 0.08 Hz
• 0.08 s

Multiple Choice

A wave has frequency of 50 Hz and a wavelength of 10 m. What is the speed of the wave?

• 500 m/s

• 50 m/s

• 5 m/s

• 0.5 m/s

Multiple Choice

If this wave chain represents 1 second, What is the frequency of the waves?

• 1 Hz

• 9 Hz

• 3 Hz

• 6 Hz

Multiple Choice

One end of the rope is vibrated to produce a wave with a wavelength of .25 m.  The Frequency of the wave is 3.0 Hz.  What is the speed of the wave?

• 3.00 m/s
• 2.50 m/s
• .75 m/s
• 1.25 m/s

Multiple Choice

what type of wave is it?

• Squishy Wave

• Transverse Wave

• longitudinal wave

• longitudinal/compression/pressure waves