Ch 11 waves and vibration , grade 10.pptx

vibration

1. Chapter 11 Vibrations and Waves Section 3 Properties of Waves

2. Objectives At the end of this section, the student will be able to: Distinguish local particle vibrations from overall wave motion. Differentiate between pulse waves and periodic waves. Differentiate between mechanical and electromagnetic waves Interpret waveforms of transverse and longitudinal waves. Relate energy and amplitude. Distinguish between period and frequency. Apply the relationship among wave speed, frequency, and wavelength to solve problems.

3. Part 1 Wave motion Waves classifications Waves characteristics

4. Wave Motion A wave is the motion of a disturbance. A medium is a physical environment through which a disturbance can travel. For example, water is the medium for ripple waves in a pond. A wave transports energy and not matter. Objective: Distinguish local particle vibrations from overall wave motion.

5. Wave Motion Objective: Differentiate between pulse waves and periodic waves. Click on the image

6. Wave Motion Click on the image

7. Wave Motion Objective: Differentiate between pulse waves and periodic waves.

8. Mechanical and electromagnetic waves Click on the picture below to watch the video Objective: Differentiate between mechanical and electromagnetic waves

9. Objective: Distinguish local particle vibrations from overall wave motion. Mechanical and electromagnetic waves

10. Objective: Differentiate between mechanical and electromagnetic waves Mechanical and electromagnetic waves A mechanical wave requires a medium to propagate An electromagnetic wave doesn’t require a medium to propagate, it can propagate in vacuum Example: Sound waves Example : Light waves

11. Transverse Waves Click on the wave below to watch the video

12. Transverse waves A transverse wave is a wave whose particles vibrate perpendicularly to the direction of the wave motion. The crest is the highest point above the equilibrium position, and the trough is the lowest point below the equilibrium position. The wavelength ( l ) is the distance between two adjacent similar points of a wave. Objective: interpret waveforms of transverse and longitudinal waves.

13. Transverse waves l Trough Crest

14. Longitudinal Waves . Click on the wave below to watch the video Objective: interpret waveforms of transverse and longitudinal waves.

15. A longitudinal wave is a wave whose particles vibrate parallel to the direction the wave is traveling. Longitudinal Waves . Objective: interpret waveforms of transverse and longitudinal waves.

16. Waves and Energy Transfer Waves transfer energy by the vibration of matter. The greater the amplitude, the more energy a wave carries. The amplitude of a wave gradually diminishes over time as its energy is dissipated. Objective: Relate energy and amplitude.

17. Self Check Multiple Choice Base your answers on the graph . 1. Which letter on the graph represents wavelength? F. A H. C G. B J. D

18. Self Check Multiple Choice Base your answers on the graph . 1. Which letter on the graph represents wavelength? F. A H. C G. B J. D

19. Self Check Multiple Choice Base your answers on the graph . 2. Which letter on the graph is used for a trough? A. A C. C B. B D. D

20. Self Check Multiple Choice Base your answers on the graph . 2. Which letter on the graph is used for a trough? A. A C. C B. B D. D

21. Self Check Multiple Choice Base your answers on the graph . 3. What kind of wave does this graph represent? A. transverse wave C. electromagnetic wave B. longitudinal wave D. pulse wave

22. Self Check Multiple Choice Base your answers on the graph . 3. What kind of wave does this graph represent? A. transverse wave C. electromagnetic wave B. longitudinal wave D. pulse wave

23. End Of Part 1 Thank you for your attention

24. Part 2 Period Frequency Speed of propagation

25. Period and Frequency of a SHM Objective: Distinguish between period and frequency. Click on the image

26. Period and Frequency of a SHM The frequency It is the number of cycles (oscillations) performed in a unit of time. Its SI unit is the Hertz (Hz) Its symbol is f. 𝑓= 𝑛/𝑡, where n is the number of cycles and t is the time. The period It is the time taken to perform one oscillation. Its SI unit is the second (s) Its symbol is T. Objective: Distinguish between period and frequency.

27. Period and Frequency of a Periodic Wave A periodic wave is often created by a SHM. All the points in the medium will have the same SHM as the source. The created wave has the same period and frequency as the SHM. A wave frequency is the number of waves that pass a fixed point per unit of time. A wave period is the time taken to complete 1 cycle. In one period the wave travels 1 wavelength l. Objective: Distinguish between period and frequency.

28. Period and Frequency of a Periodic Wave Objective: Distinguish between period and frequency. Click on the image

29. Speed of propagation of a wave The speed of a mechanical wave is constant for any given medium. The speed of a wave is given by the following equation: v = f .  wave speed = frequency  wavelength This equation applies to both mechanical and electromagnetic waves.

30. Now let’s check if you understood

31. Self Check Multiple Choice 1. Two successive crests of a transverse wave are 1.20 m apart. Eight waves pass a given point in 16.0 s. What is the wave speed? F. 0.667 m/s G. 0.800 m/s H. 1.80 m/s J. 9.60 m/s

32. Self Check Multiple Choice 1. Two successive crests of a transverse wave 1.20 m apart. Eight waves pass a given point in 16.0 s. What is the wave speed? F. 0.667 m/s G. 0.600 m/s H. 1.80 m/s J. 9.60 m/s λ = 1.20 m f = n/t = 8/16.0 = 0.500Hz V = λ . f = 1.20 x 0.500 = 0.600 m/s

33. Self Check Short Response 2. Green light has a wavelength of 5.20  10 –7 m and a speed in air of 3.00  10 8 m/s. Calculate the frequency and the period of the light. f = v/λ = 3.00  10 8 / 5.20  10 –7 = 5.77 x10 14 Hz T = 1/f = 1.73 x 10 -15 s

34. Self Check Short Response 3. What kind of waves does not need a medium through which to travel? Answer: electromagnetic waves

35. End of Section 3 Thank you for your attention