Answer:
77.96dB
Explanation:
Recall that decibels are a unit of measuring intensity of sound, and depend on the logarithm of the intensity
the intensity, measured in decibels is given by:
I(db)=10log(I/I0)
I is the intensity in MKS units; I0 is the threshold intensity for human hearing (10^-12 W/m^2)
Thus, if the two sounds together have a dB of 81, we know:
81=10log(I/I0)
using the data above, we can find the intensity of the two sounds to be
0.000125 W/m^2
therefore, one firecracker has an intensity half of that, or 0.0000625W/m^2
now use this value to find the dB of one firecracker:
I(dB0=10log(0.0000625/10^-12)=77.96dB
Answer:
A.100J
Explanation:
Given parameters:
Force on car = 20N
Distance = 5m
Unknown:
Work done = ?
Solution:
Work done is the product of force and distance;
Work done = force x distance;
Insert given parameters and solve;
Work done = 20 x 5 = 100J
Answer:
The outside layer is the wettest.
Explanation:
A bowl-shaped depression formed by a mountain glacier is termed a cirque.
