1. Light & Sound Regents Physics Mr. Rockensies

2. Homework Answers 22) 32 m 23) 0.4286 s 24) 3.03 s 25) 0 m 26) 2 m/s 27) 2 m/s 2 28) 7.35 m 29) 432 m 30) 45 m 31) 8 s 32) 22 m 33) DE 34) 1 m/s 35) CD 36) AB (accelerating); EF, GH (decelerating)

3. Law of Reflection θiθi θrθr θ i = angle of incidence θ r = angle of reflection (both measured from the normal) θ i = θ r normal Rigid Boundary

4. crest trough Orientation is inverted when reflecting off a rigid boundary

5. Wave Interactions Interference – two waves occupy the same medium at the same time. It can either be constructive or destructive. Principle of Superposition – when waves overlap, add their amplitudes

6. Before During After A1A1 A2A2 A 1 + A 2 constructive interference A2A2 A1A1

7. Before During After +A destructive interference +A -A

8. General

9. Resonance 1.Every medium has “natural frequencies” at which it likes to vibrate, due to length, tension, density, etc. 2.When vibrating at these frequencies, constructive and destructive interference keep occurring at the same place. 3.A “standing wave” is formed with Nodes (points of destructive interference) and Anti-Nodes (points of maximum constructive interference)

10. Wave Diagram AN NNNN Sympathetic Vibration – When one object resonates, a second nearby object begins to vibrate at the same frequency