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:
w=3.05 rad/s or 29.88rpm
Explanation:
k = coefficient of friction = 0.3900
R = radius of the cylinder = 2.7m
V = linear speed of rotation of the cylinder
w = angular speed = V/R or to rewrite V = w*R
N = normal force to cylinder
N=


These must be balanced (the net force on the people will be 0) so set them equal to each other.





There are 2*pi radians in 1 revolution so:

So you need about 30 RPM to keep people from falling out the bottom
It is because you drink a lot of water. So the less water you drink the more yellow it is. It means you have healthy urine.
The first experiment that was made to attempt to measure the speed of light involved detonating gunpowder by Isaac Beeckman. He declared that his experiment was inconclusive. Galileo also tried to measure the speed of light using two lanterns placed across each other. The next experiment involved planets where Ole Romer based his calculation on its movements. The final calculations were derived from different theories by different scientists including Maxwell until it ended up with the exact value for the speed of light.