Home
Subjects
Create
Search
Log in
Sign up
Upgrade to remove ads
Only $2.99/month
Science
Physics
Acoustics
Physics Week 2
STUDY
Flashcards
Learn
Write
Spell
Test
PLAY
Match
Gravity
Terms in this set (25)
From Hooke's law, the restoring force acts as a in a stretched or compressed spring is...
F=kx
The restoring force in a vertical spring is...
F=mg
F =
kx = mg
The elastic potential energy 𝑈s depends on
the spring constant 𝑘k and the distance 𝑥x that the spring has stretched from its un-stretched length
𝑈s=1/2𝑘𝑥^2
The gravitational potential energy 𝑈gUg depends on
the mass 𝑚m hung from the spring, the acceleration 𝑔g due to gravity, and the height 𝑦y of the mass.
𝑈g=𝑚𝑔𝑦
how would you calculate:
Energy from the Sun arrives at the top of the Earth's atmosphere with an intensity of 1.36 kW / m2. How long does it take for 2.75 × 109 J to arrive on an area of 3.75 m2?
The energy that arrives to the specific area is defined as radiating power multiplied by time:
E = PT
(1) At the same time, the power of radiating delivered to a specific area is equal to intensity per square unit multiplied by the area:
P = pA
(2) Combining (1) and (2):
E = pAT
(3) Solving (3) for T, one can define the time requested:
T=E/pA
The expression for the distance between a maximum and its corresponding minimum is,
y=2a
Here, y is the distance between a maximum and its corresponding minimum and a is the amplitude of the wave.
The period 𝑇 is
The period 𝑇 is the time required for a single cycle to pass a stationary observer. It is
𝑇=1/𝑓
The requested time interval Δt required for the given number (𝑛) of cycles to pass a stationary observer is thus
Δ𝑡=𝑛𝑇=𝑛𝑓
The length along the string of a single cycle is
the given wavelength 𝜆.
The number 𝑁N of cycles in the given length 𝐿L of string is
𝑁=𝐿/𝜆
The note that the musician plays is a sound wave, which is a
longitudinal traveling wave.
At a fixed point in space, this traveling wave becomes just an oscillation in the local air pressure.
The time between one pressure maximum and the next is called
the period and is the inverse of the frequency
T=1/f
The time that it takes for 571571 air pressure maxima to pass a point in space is
571571 multiplied by the period.
Δ𝑡=(571)𝑇
=571/𝑓
=571/392 Hz
=1.46 s
You would like to express the air pressure oscillations at a point in space in the given form.
𝑃(𝑡)=𝑃maxcos(𝐵𝑡)
If 𝑡 is measured in seconds, what value should the quantity 𝐵 have?
You would like to express the air pressure oscillations at a point in space in the given form.
𝑃(𝑡)=𝑃maxcos(𝐵𝑡)P(t)=Pmaxcos(Bt)
If 𝑡 is measured in seconds, what value should the quantity 𝐵 have?
To express the air pressure oscillations in the given form, the quantity 𝐵 must be
the angular frequency, 𝜔.
𝑃(𝑡)=𝑃maxcos(𝜔𝑡)
This is because the argument of the cosine function must be in angular units. The air pressure oscillates once every period,
whereas the cosine function repeats every 2𝜋2π radians. Thus,
the product of 𝜔 and the period should be equal to 2𝜋 radians.
𝜔𝑇=2𝜋 radians
Solving this relationship for ω gives the definition of angular frequency, which can then be found from either the period or the frequency.
𝜔=2𝜋 radians/𝑇
=(2𝜋 radians)*𝑓
=(2𝜋 radians)×(392 Hz)
=2460radians/s
To find the power output 𝑃 use
the definition of intensity
𝐼=𝑃/𝐴
define the terms 𝑃=𝐼𝐴
P =Power
I= intensity
A= area
*if given dimensions you can plug them in to solve for A
To find the ratio of wavelengths of sound in air and seawater, use the equation
𝑣=𝑓𝜆
where 𝑣 is the velocity of the wave, 𝑓 is the frequency, and 𝜆 is the wavelength.
You can write two equations, one for each of the materials.
𝑣air=𝑓𝜆air
𝑣seawater=𝑓𝜆seawater
Then, you can divide the first equation by the second to get
(𝑣air/𝑣seawater)=(𝑓𝜆air/𝑓𝜆seawater)=(𝜆air/𝜆seawater)
The speed of sound in air must be calculated from
the air temperature, 𝑇
The wave speed 𝑣 is
𝑣=𝜙𝑐
where 𝜙 is the given factor and 𝑐 denotes the speed of light in vacuum, which is 3.00×108 m/s3.00×108 m/s.
For all periodic waves, the wave speed 𝑣v, frequency 𝑓f, and wavelength 𝜆λ are related by
𝜆=𝑣/𝑓=𝜙𝑐/𝑓
The amplitude of the combined waves = 0.
destructive interference.
constructive interference.
The amplitude of the combined wave is twice the amplitude of the moving waves.
standing wave.
We can see from the lower pair of graphs the vertical displacement of some points is zero for all times(called nodes).
When two periodic waves of slightly different frequencies interfere, the result is an alternation between constructive and destructive interference at each point. These alternations, which have their own characteristic frequency, are referred to as
beats
Other sets by this creator
Bioc Unit 3
46 terms
Biochem Unit 2
120 terms
exam review day 2
124 terms
AMINO ACIDS
36 terms
Other Quizlet sets
Econ 304
24 terms
Pharm L3: G-protein coupled receptors
38 terms
CHEM 1212: Exp. 3: Synthesis of Copper (II) Saccha…
12 terms