# Answer Checking: Unit 1 Waves Chapter 1

1. Aug 26, 2014

### Codav

1. I'll just post the entire question list for this chapter in image format.

http://imgur.com/retjkzJ

1.
i) The amplitude is the measurement of the wave from the equilibrium point to the trough or crest of a wave. The wavelength is the measurement of two successive points of a wave.

ii) There are three cycles in this wave. Three cycles have traveled a total of 4.8m. Therefore:
λ=4.8/3
λ=1.6m
The wavelength is 1.6m

iii)The time for the wave to travel 4.8m is 6s.
Speed Equation: Δd/Δt=v
4.8m/6s=0.8m/s
The wave's speed is 0.8m/s
Finding Frequency
v=λ*ƒ
0.8m/s=1.6m*ƒ
0.8m/s/1.6m=ƒ
ƒ=0.5Hz
The frequency is 0.5Hz.

iv) Speed remains the same because the wave is traveling the same distance over the same amount of time (4.8m over 6s).
Speed is 0.8m/s
Finding the wavelength: We know frequency is now 2Hz.
v=λ*ƒ
0.8m/s=λ*2Hz
0.8m/s/2Hz=λ
λ=-0.4m
The wavelength is 0.4m.
The higher the energy, the larger the frequency and the shorter the wavelength.

2) Differences:
Transverse waves have perpendicular vibration to the direction of the wave. Longitudinal waves have parallel vibration to the direction of the wave. They both have wavelength, amplitude and frequency.

The wavelength is the measurement between two successive points of a wave. The amplitude is the measurement of a wave from the equilibrium point to the trough or a crest of a wave. They both refer to properties of a wave.

The period is the time for a wave to complete one cycle. The frequency is how often particles vibrate when a wave passes through the medium. The two equations are complimentary:
ƒ=1/T, T=1/ƒ

3)http://imgur.com/4zkNzqn

4) 16 cycles in 8s.
T=Δt/N
T=8/16
T=.5s
The period is .5s
ƒ=1/T
ƒ=1/.5s
ƒ=2Hz
The frequency is 2Hz
How long would it take the pendulum to complete 5 cycles?
1 cycle=.5s
0.5s*5=2.5s
It would take the pendulum 2.5s to complete 5 cycles.

2. Aug 26, 2014

### BiGyElLoWhAt

For the most part it looks good, but I'm not so sure about your definition of frequency in #2 part iii, or however you wanna label it.