1. WAVES  Komang Gde Suastika  Physics Dept  Palangka Raya University  Email: suastika358@yahoo.com

2. What do you know? About waves?

3.  Tujuan 1. By the end of this lesson you will be able to: State that a wave transfers energy. 2. Use the following terms correctly in context: wave, frequency, wavelength, speed, amplitude, period. 3. State the difference between a Mechanical Waves and a Electromagnetic waves (EM Waves), and give an example of each. 4. State the difference between a longitudinal wave and a transverse wave, and give an example of each.

4. Perhatikan Fenomena berikut

5. WAVES a disturbance that transfers energy

6. Waves transfer energy…

8. CHARACTERISTICS OF WAVES Waves are described according to their  Amplitude measures DISPLACEMENT size of the disturbance  Wavelength distance of a “repeating unit” Also called a cycle  Velocity v speed = how fast wave travels

9. AMPLITUDE Distance between “rest & crest” or “rest & trough” Distance between “rest & crest” or “rest & trough” Gives indication of “power” or “strength” of wave (magnitude of earthquake = Richter scale) Gives indication of “power” or “strength” of wave (magnitude of earthquake = Richter scale) Does not affect velocity of wave Does not affect velocity of wave Determines loudness (sound) or brightness (EM wave) Determines loudness (sound) or brightness (EM wave)

10. WAVELENGTH WAVELENGTH  Distance between any two repeating points on a wave crest-crest, trough-trough, expansion-expansion, compression-compression  Determines what colors we see; what notes we hear (pitch)  Shorter wavelengths have more cycles per minute because they aren’t as long

11. VELOCITY v  the rate at which the energy travels; speed & direction  Depends on medium Mechanical waves travel faster through dense mediums Mechanical waves travel faster through dense mediums EM Waves are faster through less dense mediums EM Waves are faster through less dense mediums

12. Frequency ƒ  measured in wavelengths/second or cycles/second Hertz (Hz) = number of wavelengths in 1 second  Frequency is related to velocity: v = ƒ  Frequency is related to velocity: v = ƒ  How often number of wavelengths that pass any point per second

13. PERIOD T  How long Amount of time for one wavelength to pass a point  Related inversely to frequency 1 = 1 Tf Period = 1 Frequency

14. Properties of Waves  What is meant by the axis of a wave? The axis is the line running through the middle of the wave pattern.

15. What is meant by the crest of the wave? The crest is the top part of the wave

16. …and the trough? The trough is the bottom part of the wave.

17. What is the amplitude of the wave? The amplitude is the distance from the axis to the crest

18. or from axis to trough.

19. Definition of Wavelength? The wavelength is the distance after which the wave pattern repeats itself – the distance between two identical points on the wave

20. Wavelength is given the symbol λ pronounced lambda.

21. Frequency  The frequency of the wave is the number  of waves each second.  It is measured in hertz (Hz) which just  means “per second”.

22. Frequency  Calculate the frequency of each of the following waves: following waves:  125 waves passing a point in 10 seconds.  16 waves passing a point in 24 seconds.  30 waves passing a point in 1 minute.

23.  Carries energy from one place to another  Classified by what they move through 1. Mechanical Waves the energy is transferred by vibrations of medium (medium = matter) ex/ ocean waves move through water 2. Electromagnetic waves (EM Waves) the energy moves through disturbances in the electromagnetic field.

24. WAVE STRUCTURE CREST (peak) AMPLITUDE resting to max peak WAVELENGTH TROUGH

25. MECHANICAL WAVES travel through & gradually lose energy to that medium  Examples: water, sound, rope, & spring waves water, sound, rope, & spring waves  Mechanical Media: water, air, rope, spring water, air, rope, spring require a medium ( the material through which the disturbance is moving) to transmit energy Making a pulse

26. MECHANICAL WAVES Classified by how medium vibrates Pulse = direction of energy transfer Vibration = direction of vibration of medium relative to pulse 3 typestypes: Longitudinal,transverse,surface

27. MECHANICAL WAVES Classified by how medium vibrates Longitudinal Waves: Vibration is in the same direction as wave pulse (parallel to wave pulse) Transverse Waves: Vibration is at 90 0 (right angles) to wave pulse Surface Waves: Vibration is circular Ex/ Ocean waves; surface waves

28. TRANVERSE WAVES  Sideways or up & down  Examples: S-type earthquake waves S-type earthquake waves Electromagnetic (EM) or light waves Electromagnetic (EM) or light waves Vibration is perpendicular to the direction of the motion of the wave

29. LONGITUDINAL WAVES  Back and forth (compression & rarefraction)  Also called compression or pressure wave  Examples: P-type earthquake waves P-type earthquake waves Sound waves Sound waves Vibration is parallel to the direction of the motion of the wave Rarefraction (expansion) Compression

30. Waves describe the Earth S waves move through solids only!!! P waves move through solids & liquids Are these MECHANICAL WAVES???? YES!! Seismic waves need a medium (the earth!)

31. Penjalaran Gelombang dalam Satu Dimensi Fungsi Gelombang : Menjalar ke kanan Menjalar ke kiri Cepat-rambat Gelombang (Kecepatan Fasa) :

32. Superposisi dan Interferensi Gelombang

36. Gelombang Bunyi

37. Cepat-rambat Gelombang di dalam Dawai Tegangan dawai Massa dawai persatuan panjang Refleksi dan Transmisi Gelombang

38. Rambatan gelombang dari medium kurang rapat ke medium yang lebih rapat Rambatan gelombang dari medium lebih rapat ke medium yang kurang rapat

39. Harmoni Gelombang A

40. Untuk Gelombang yang Menjalar ke kanan atau

42.  PERSAMAAN GELOMBANG x x  f (x)t = 0  c t f (x - ct)

43.  Gelombang Sinusoidal Dalam Domain Ruang Amplitudo x  A Panjang gelombang Bilangan gelombang x

44.  Gelombang Sinusoidal Dalam Domain Waktu t  A T Perioda Amplitudo Frekuensi sudut Frekuensi

45.  Dalam Domain Ruang Dan Waktu

46. Sebuah gelombang perpindahan dinyatakan dengan :  (x,t) = 0,02 sin [ 2  ( 0,5 x – 10 t ) ] m Tentukan panjang gelombang, frekuensi dan kecepatannya.  Contoh

47. Jawab :

48. Tugas Tugas  Persamaan suatu gelombang yang bergerak transversal Dimana x dan y dalam cm dan t dalam detik. Berapa amplitudo, panjang gelombang, frekuensi dan kecepatan rambat gelombang itu