WAVES SIMPLE HARMONIC MOTION SIMPLE HARMONIC MOTION PROPERTIES OF WAVES PROPERTIES OF WAVES WAVE INTERFERENCE WAVE INTERFERENCE SOUND WAVES SOUND WAVES

Telephone TEST - 50 points Write your set of 5 words for transmission. Write words you heard in 1 minute. Take turns. Repeat for a different phone. Describe the clarity of transmission of data Using : a. String Phone b. Shorter String Phone c. Fishing line Phone d. Shorter Fishing line Phone e. Wire Phone f. Shorter Wire Phone LABORATORY REPORT – 50 POINTS Purpose : Determine the best medium( string. Fishing line, wire) to transmit sound waves.Why ? What is the effect of the length of the medium to sound wave transmission. Materials : Data Table Conclusion :

Pendulum Motion Packet Groups of 4 a. Force Analysis Of Pendulum b. Sinusoidal Nature of a Pendulum c. Energy analysis d. Period of A Pendulum Read your topic – 20 minutes Take Notes Share your information – 5minutes /each person. Write and number all the information about pendulum regarding all subtopic on paper. Score it.

Pendulum Experiment

Spring Motion Packet Groups of 5 a. Hooke’s Law b. Force Analysis Of Spring c. Sinusoidal Nature of a Spring d. Energy analysis e. Period of A Spring Read your topic – 15 minutes Take Notes Share your information – 5minutes /each person. Write and number all the information about pendulum regarding all subtopic on paper. Score it.

Spring Experiment I. Purpose : To determine the relation of the Force (Fs) on the stretch length (x) of the spring. To calculate the Spring constant. To calculate the period and frequency of the spring using T = 2Π m/k II. Materials : Springs, 10 g, 2- 20g, 50g Springs, 10 g, 2- 20g, 50g III. Background Information and Physics Concepts 2 paragraphs about Springs 2 paragraphs about Springs IV. Diagram Set Up – Draw and label the experiment set up

SIMPLE HARMONIC MOTION Motion that is repeating or periodic. Motion that is repeating or periodic. Two types Two types Spring Spring Hooke’s Law states that the restoring force is proportional to the displacement Hooke’s Law states that the restoring force is proportional to the displacement F = -kx F = -kx Units: Newtons Units: Newtons Negative: direction of the Force is opposite the displacement. Negative: direction of the Force is opposite the displacement.

SIMPLE HARMONIC MOTION

Stretch or compression provides three types of energy. Stretch or compression provides three types of energy. Max displacement Max displacement EPE = ½ k x 2 EPE = ½ k x 2 V = 0 V = 0 A increase to max A increase to max Equilibrium position Equilibrium position Min x Min x Max KE Max KE Max velocity Max velocity a = 0 a = 0

SIMPLE HARMONIC MOTION Horizontal springs: Horizontal springs: EPE elastic EPE elastic KE KE Vertical springs: Vertical springs: PE gravitational PE gravitational EPE elastic EPE elastic KE KE Conservation of energy applies Conservation of energy applies Friction or damping force Friction or damping force

SIMPLE HARMONIC MOTION Period of a spring Period of a spring T = 2  √ m/k T = 2  √ m/k Units: sec/cycle or sec/revolution or sec Units: sec/cycle or sec/revolution or sec f = 1 / T f = 1 / T Units: cycle/sec or revolution/sec or Hertz or s -1 Units: cycle/sec or revolution/sec or Hertz or s -1

SIMPLE HARMONIC MOTION Simple pendulum Simple pendulum For small angles For small angles Restoring force is proportional to x. Restoring force is proportional to x. Work done is ZERO Work done is ZERO Max PE at the highest point Max PE at the highest point Max KE at the lowest point Max KE at the lowest point Period of a pendulum Period of a pendulum T = 2  √ l/g T = 2  √ l/g Units: sec/cycle or sec/revolution or sec Units: sec/cycle or sec/revolution or sec

SIMPLE HARMONIC MOTION

CW: Problems P P ,3,4,10,11,12,13,14,16a- b,20,21,32,33,34,35,,38,39,44,47,49 2,3,4,10,11,12,13,14,16a- b,20,21,32,33,34,35,,38,39,44,47,49

PROPERTIES OF WAVES Follows a simple harmonic motion Follows a simple harmonic motion Needs a source Needs a source Medium = matter Medium = matter Matter does NOT travel only energy Matter does NOT travel only energy Mechanical waves need a medium to travel Mechanical waves need a medium to travel EM does not need a medium to travel EM does not need a medium to travel Pulse: single wave Pulse: single wave

CW : Two Types of Waves Venn Diagram P 459 – 460

PROPERTIES OF WAVES Two types of waves Two types of waves Transverse waves Transverse waves Disturbance is perpendicular to the propagation Disturbance is perpendicular to the propagation EM EM

PROPERTIES OF WAVES Longitudinal or compressional waves Longitudinal or compressional waves Disturbance is parallel to the propagation Disturbance is parallel to the propagation Sound waves Sound waves

PROPERTIES OF WAVES Parts of the wave Parts of the wave Wavelength ( ): length of a wave measured between two consecutive identical points Wavelength ( ): length of a wave measured between two consecutive identical points Frequency (f) Frequency (f) Period (T) Period (T) Amplitude (A): max height of the wave Amplitude (A): max height of the wave

PROPERTIES OF WAVES Crest: highest point of transverse wave Crest: highest point of transverse wave Trough: lowest point of transverse wave Trough: lowest point of transverse wave

PROPERTIES OF WAVES

Compression: high density portion of compressional wave Compression: high density portion of compressional wave Rarefaction: low density portion of compressional wave Rarefaction: low density portion of compressional wave

PROPERTIES OF WAVES

Wave Equation Speed = frequency x wavelength Speed = frequency x wavelength c = f c = f v = f v = f c = speed of light = 3.0 x 10 8 m/s c = speed of light = 3.0 x 10 8 m/s

CW:Problems p

Reading CW Properties of the Wave Wave Characteristics

WAVE INTERFERENCE Energy travels…NOT matter Superposition Principle: two or more waves will combine algebraically Waves pass through without altering their shapes and size.

WAVE INTERFERENCE Constructive: resulting wave is larger in amplitude In phase

WAVE INTERFERENCE Destructive: resulting wave is smaller in amplitude Out of phase

WAVE INTERFERENCE

WAVE BEHAVIOR Determining behavior when wave reaches a boundary (interface between two medium) Determining behavior when wave reaches a boundary (interface between two medium) Incident pulse: incoming wave Incident pulse: incoming wave Reflected pulse: a wave bouncing off a boundary Reflected pulse: a wave bouncing off a boundary Transmitted pulse: wave continuing through to next medium Transmitted pulse: wave continuing through to next medium Upright Upright Inverted Inverted

WAVE BEHAVIOR Reflection: wave hits a boundary and returns Reflection: wave hits a boundary and returns Newton’s third law Speed and wavelength are the same Amplitude is smaller

WAVE BEHAVIOR

Transmitted: slower than reflected and smaller wavelength Reflected: speed and wavelength are same as incident

WAVE BEHAVIOR Transmitted: faster and larger wavelength Reflected: same speed and wavelength as incident

WAVE BEHAVIOR Refraction: change in direction of waves traveling from one medium to another Refraction: change in direction of waves traveling from one medium to another Speed and wavelength changes Speed and wavelength changes

WAVE BEHAVIOR Diffraction: change in direction of waves as the wave passes through opening or around a barrier.

SOUND WAVES Compressional or longitudinal wave Compressional or longitudinal wave High pressure and low pressure region High pressure and low pressure region Speed depends on medium Speed depends on medium v solid > v liquid > v gas Speed depends on temperature Speed depends on temperature Direct relationship 343 m/s at room temperature

SOUND WAVES

Range of sound 20 to Hz Range of sound 20 to Hz Infrasonic, audible, ultrasonic Infrasonic, audible, ultrasonic Measured in decibels Measured in decibels Loudness is not intensity but related to amplitude of the wave Loudness is not intensity but related to amplitude of the wave Energy of the wave is proportional to A 2 Energy of the wave is proportional to A 2 Intensity is power / area Intensity is power / area

STANDING WAVES Standing waves: reflected and incident wave interact to appear to be standing Standing waves: reflected and incident wave interact to appear to be standing Antinodes: largest amplitude Antinodes: largest amplitude Nodes: zero amplitude Nodes: zero amplitude

STANDING WAVES

L = /2 L = /2 L = 2 / 2 = L = 2 / 2 = L = 3 / 2 L = 3 / 2 L = 4 / 2 = 2 L = 4 / 2 = 2

STANDING WAVES Increases by increments of /2 Increases by increments of /2 Longest wavelength: L = n /2 Longest wavelength: L = n /2 where n = 1, 2, 3, 4…… Fundamental frequency: lowest frequency Fundamental frequency: lowest frequency v = f v = f f = v / = nv / 2L Harmonics: multiples of the fundamental frequency Harmonics: multiples of the fundamental frequency

OPEN PIPES L = /2 L = /2 L = 2 / 2 = L = 2 / 2 = L = 3 / 2 L = 3 / 2 L = 4 / 2 = 2 L = 4 / 2 = 2

OPEN PIPES Increases by increments of /2 Increases by increments of /2 Longest wavelength: L = n /2 Longest wavelength: L = n /2 where n = 1, 2, 3, 4…… Fundamental frequency: lowest frequency Fundamental frequency: lowest frequency v = f v = f f = v / = nv / 2L

CLOSED PIPES L = /4 L = /4 L = 3 / 4 L = 3 / 4 L = 5 / 4 L = 5 / 4 L = 7 / 4 L = 7 / 4

CLOSED PIPES Increases by increments of /2 Increases by increments of /2 Longest wavelength: L = n /4 Longest wavelength: L = n /4 where n = 1, 3, 5…… Fundamental frequency: lowest frequency Fundamental frequency: lowest frequency v = f v = f f = v / = nv / 4L

DOPPLER EFFECT Approaching Approaching Wavelength decreases Wavelength decreases Speed constant Speed constant Frequency increases Frequency increases Pitch = frequency Pitch = frequency Leaving Wavelength increases Speed constant Frequency decreases

DOPPLER EFFECT Determine the movement of Stars and Planets Determine the movement of Stars and Planets Blue Shift Blue Shift wavelength decreases frequency increases approaching Red Shift Red Shift wavelength increases frequency decreases leaving

DOPPLER EFFECT

BOW/SHOCK WAVES Bow waves: waves overlap at the edges and the pattern made by the overlapping waves is a V shape; 2-D Bow waves: waves overlap at the edges and the pattern made by the overlapping waves is a V shape; 2-D Shock waves: 3-D Shock waves: 3-D Sonic boom: sharp crack heard when the object breaks the overlapping waves barrier Sonic boom: sharp crack heard when the object breaks the overlapping waves barrier

BOW/SHOCK WAVES V of object < V of wave

BOW/SHOCK WAVES V of object = V of wave V of object > V of wave

RESONANCE Natural frequency: frequency in which an object vibrates when hit Natural frequency: frequency in which an object vibrates when hit Resonance: vibrating object matches the natural frequency of an object and increasing the amplitude Resonance: vibrating object matches the natural frequency of an object and increasing the amplitude

RESONANCE

BEATS Two or more sounds wave interfere constructively or destructively producing sound as beats Two or more sounds wave interfere constructively or destructively producing sound as beats Beats = |f 1 – f 2 | Beats = |f 1 – f 2 |