Answer: The intensity level of sound in the bedroom is 80dB
Explanation:
Intensity of lawn mower at r=1m is 100dB
Beta1= 10dBlog(I1/Io)
100dB= 10dB log(I1/Io)
10^10= I1/Io
I1= Io(10^10)
10^12)×(10^10)= I1
I1=10^-2w/m^2
Intensity of lawn mower at r=20m
I2/I1=(r1/r2)^2 =(1/20)^2
I2= I1(1/400)
I2=2.5×10^-3W_m^2
Intensity of 4 lown mowers at 20m fro. Window
= 10dBlog(4I2/Io)
= 10^-4/10^-12
=80dB
Answer:
14 N
Explanation:
The tension in the second string is puling both the masses of 20 kg and 8 kg with acceleration of 0.5 m s⁻²
So tension in the second string = total mass x acceleration
= 28 x .5 = 14 N . Ans..
Answer:
17.66 kPa
Explanation:
The volume of water in the swimming pool is the product of its dimensions
V = 30 * 8.7 * 1.8 = 469.8 cubic meters
Let water density 
, and g = 9.81 m/s2 we can calculate the total weight of water in the swimming pool
The area of the bottom
A = 30 * 8.7 = 261 square meters
Therefore the pressure is its force over unit area
or 17.66 kPa
