Qualification > Sciences
CIE physics paper 2
Tyserius:
I hate questions where they ask you to explain what will happen when the scenario changes... Must make sure it is with reference to the equations, logic and physics principles. So annoying!
falafail:
--- Quote from: Tyserius on November 15, 2009, 03:26:00 pm ---I hate questions where they ask you to explain what will happen when the scenario changes... Must make sure it is with reference to the equations, logic and physics principles. So annoying!
--- End quote ---
agh, yeah. i don't like written questions, i'd rather calculate thingssssssss
By the way, can you check out the questions i posted on the first page? tumble bug did a few but she/he didn't know about some of them D:
Tumble Bug:
--- Quote from: falafail on November 15, 2009, 03:27:51 pm ---agh, yeah. i don't like written questions, i'd rather calculate thingssssssss
By the way, can you check out the questions i posted on the first page? tumble bug did a few but she/he didn't know about some of them D:
--- End quote ---
lol...im a SHE...hheheh...
MaNi_DaDuDe:
--- Quote from: saadiyah on November 15, 2009, 01:05:47 pm ---plz can u help me with this question?
A point source of sound radiates energy uniformly in all directions. At a distance of 3.0 m from source, the amplitude of vibration of air molecules is 1.0 X 10-7 m. Assuming that no sound energy is absorbed, calculate the amplitude of vibration at a distance of 5 m from source.
Answer is 6.0 x 10-8 m.
--- End quote ---
Cross multiply. :]
Tyserius:
--- Quote from: saadiyah on November 15, 2009, 01:05:47 pm ---plz can u help me with this question?
A point source of sound radiates energy uniformly in all directions. At a distance of 3.0 m from source, the amplitude of vibration of air molecules is 1.0 X 10-7 m. Assuming that no sound energy is absorbed, calculate the amplitude of vibration at a distance of 5 m from source.
Answer is 6.0 x 10-8 m.
--- End quote ---
As I = ka2 and is directly proportional to 1/r2,
ka2 = m/r2 (m is the other constant)
And since r is increased from 3.0m to 5.0m the new r, r' is = 5/3 r
So to find your new amplitude, a' :
ka'2 = m/(5/3 r)2
ka'2 = m/(25/9 r2)
ka'2 = 9/25 m/r2
ka'2 = 9/25 (ka2) << Substitute from ka2 = m/r2
a' = 3/5 a
= 3/5 (1.0 x 10-7)
= 6.0 x 10-8m
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