Presentation on theme: "Answer the following… 17. What happens to the amplitude of a pulse as it travels down the slinky and back? 18. What happens to the speed of a pulse as."— Presentation transcript:
1 Answer the following…17. What happens to the amplitude of a pulse as it travels down the slinky and back?18. What happens to the speed of a pulse as it travels down the slinky and back?19. What do you observe about a pulse after it reaches the end of the medium that is fixed in place?20. What do you observe about a pulse after it reaches the end of a medium that is free to move?21. What would happen to a wave pulse on a spring if it encountered a new spring with different characteristics?
2 When a pulse encounters a medium boundary 2 things happen… ReflectionSome energy of the wave pulse is bounced back into the original medium.TransmissionSome energy of the wave pulse passes through the boundary into the new medium
3 Fixed End ReflectionAt a fixed boundary, waves are inverted as they are reflected.
4 Free End ReflectionAt a free boundary, waves are reflected on the same side of equilibrium
5 Transmission If the wave pulse goes from… Low density High density mediumReflected pulse is invertedTransmitted pulse is uprightHigh density Low density mediumReflected pulse is uprightTransmitted pulse is upright
6 What happens when wave pulses move through a medium at the same time?
7 What happens when wave pulses move through a medium at the same time? When this occurs, waves are said to experience interference
8 Wave Interference is described by the Superposition Principle…
9 Wave Interference is described by the Superposition Principle… Wave pulses (energy) pass through each other completely unaffected
10 Wave Interference is described by the Superposition Principle… Wave pulses (energy) pass through each other completely unaffectedThe medium will be displaced an amount equal to the vector sum of what the waves would have done individuallyThis results in two different types of interference: constructive and destructive
11 Constructive Interference Pulses must meet when on the same side of equilibrium.The resultant displacement of the medium greater than both originals
12 Destructive Interference Pulses must meet when on opposite sides of equilibrium.The resultant displacement of the medium is less than at least one original
14 Standing WavesAn interference pattern that results when two waves of the same frequency, wavelength, and amplitude travel in opposite directions and interfere.
15 Standing wave partsNode – point that maintains zero displacement, complete destructive interferenceAntinode – point at which largest displacement occurs, constructive interference
16 Standing wavesOnly specific frequency-wavelength combinations will produce standing wave patterns in a given medium.
17 From the standing wave lab… Frequency and wavelength are inversely proportional for a wave in a given medium.v = fv – velocity of wave (constant for a given medium)f – frequency of the wave, # of waves per second – wavelength, how far the wave travels in a single periodRemember that f = 1/T, so the equation above could also be written as 𝒗= 𝝀 𝑻