ToughSTEM
Sign Up
Log In
ToughSTEM
A question answer community on a mission
to share Solutions for all STEM major Problems.
Cant find a problem on ToughSTEM?
0
The graph shows the US Department of Labor noise regulation for working without ear protection. A machinist is in an environment where the ambient sound level is of 85 dB, i.e., corresponding to the 8 Hours/day noise level. The machinist likes to listen to music, and plays a Boom Box at an average level of 86.0 dB.


1) Calculate the INCREASE in the sound level from the ambient work environment level (in dB).

2) A student at a rock concert has a seat close to the speaker system, where the average sound intensity corresponds to a sound level of 112 dB. By what factor does that sound intensity exceed the 2- Hours/day intensity limits from the graph?
Edit
Added Thu, 18 Jun '15
Community
1
Comment
Add a Comment
Solutions
0
(a) 
The ambient sound level is of 85 dB. 8 Hours/day noise level

Boom Box at an average level of 86.0 dB

Lets turn the dB levels in powers of 10. To do this simply divide the dB level by 10.

85 = 10^(8.5)
86 = 10^(8.6)

The sound level due to ambient work environment and music is

10log(10^(8.5) + 10^(8.6)) = 88.539 dB

Therefore, the increase in sound level from the ambient work environment level (in dB).

88.539 - 85 = 3.539 dB i.e. 3.54 rounded (2dp)

(b)
The sound intensity for 2- Hours/day from the graph=95dB

A student at a rock concert has a seat close to the speaker system, where the average sound intensity corresponds to a sound level of 112 dB.

2 hours/day sound level is 95 dB (0.003162 W/m²). 
Rock concert sound level is 112 dB (0.158489 W/m²). 
ratio = 0.630957 / 0.005012 = 50.12 

The factor that exceed the 2 hours/day limits is 50.
Edit
Added Thu, 18 Jun '15
Community
1
Comment
Add a Comment
Add Your Solution!
Close

Click here to
Choose An Image
or
Get image from URL
GO
Close
Back
Add Image
Close
What URL would you like to link?
GO
α
β
γ
δ
ϵ
ε
η
ϑ
λ
μ
π
ρ
σ
τ
φ
ψ
ω
Γ
Δ
Θ
Λ
Π
Σ
Φ
Ω
Copied to Clipboard

Add Your Solution
Sign Up
to interact with the community. (That's part of how we ensure only good content gets on ToughSTEM)
OR
OR
ToughSTEM is completely free, and its staying that way. Students pay way too much already.
Almost done!
Please check your email to finish creating your account!
Welcome to the Club!
Choose a new Display Name
Only letters, numbers, spaces, dashes, and underscores, are allowed. Can not be blank.
Great! You're all set, .
A question answer community on a mission
to share Solutions for all STEM major Problems.
Why
The Purpose
How
The Community
Give Feedback
Tell us suggestions, ideas, and any bugs you find. Help make ToughSTEM even better.