Week 3 - Focus of Activity

1. λ=v/f.  333/1000 = 0.333 metres.
Remembering the Vfλ triangle/calculations are important here.
I learned acoustic waves travel with the speed (velocity) of sound, 333m/s.
2.  λ=v/f. 5000/440 = 11.4 metres.
I learned concert pitch is 440Hz.
Through a steel which is a solid, sound travels through steel at 5,000m/s
I am assuming the question I am being asked is the wavelength of the sound when it is travelling through the tuning fork.
3. f=v/λ. 333/3.33 = 100Hz.
Sound travels quickest through a solid with the particles being so close together.
4. The duration of a cycle is a second divided by the frequency.
So the duration of the cycle with a frequency of 20Hz is:
1/20s = 0.05 seconds.
5. A standing wave can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions.
A real life example of this is gliders using standing waves that form in the lee of mountain ranges to their advantage.

6. Where two waves meet, their effects are added together. This is called interference.
When they arrive in step, they reinforce each other to give a wave of greater amplitude. This is called constructive interference.
When they arrive out of step, they cancel out. This is called destructive interference.
7. The amplitude of an acoustic wave determines its loudness.
8. Decibel is used to indicate the level of acoustic waves and electronic signals. The logarithmic scale can describe very big or very small numbers with shorter notation.
9. A 1KHz tone has a period of 1/1000 or 0.001s. So it will take 20/0.001 = 20,000 seconds
A 10Hz tone has a period of 1/10 or 0.1s. So it will take  20/0.1 = 200 seconds.
10. The speed of sound in water is slower than in a solid because the particles are more spaced out, however, it is faster than in air because the particles are closer together.