6 months with no sunrise and the other 6 without a sunset, at some places on Earth, are the result of the orientation of Earth's axis.
Answer:
2.83m
Explanation:
The information that we have is
Intensity at 2.0 m:
and ![r_{1}=2m](https://tex.z-dn.net/?f=r_%7B1%7D%3D2m)
we need an intensity level of: ![I_{2}=40dB](https://tex.z-dn.net/?f=I_%7B2%7D%3D40dB)
thus, we are looking for the distance
.
which we can find with the law for intensity and distance:
![(\frac{r_{2}}{r_{1}} )^2=\frac{I_{1}}{I_{2}}](https://tex.z-dn.net/?f=%28%5Cfrac%7Br_%7B2%7D%7D%7Br_%7B1%7D%7D%20%29%5E2%3D%5Cfrac%7BI_%7B1%7D%7D%7BI_%7B2%7D%7D)
we solve for
:
![\frac{r_{2}}{r_{1}}=\sqrt{\frac{I_{1}}{I_{2}} }\\\\r_{2}=r_{1}\sqrt{\frac{I_{1}}{I_{2}} }](https://tex.z-dn.net/?f=%5Cfrac%7Br_%7B2%7D%7D%7Br_%7B1%7D%7D%3D%5Csqrt%7B%5Cfrac%7BI_%7B1%7D%7D%7BI_%7B2%7D%7D%20%7D%5C%5C%5C%5Cr_%7B2%7D%3Dr_%7B1%7D%5Csqrt%7B%5Cfrac%7BI_%7B1%7D%7D%7BI_%7B2%7D%7D%20%7D)
and we substitute the known values:
![r_{2}=(2m)\sqrt{\frac{80dB}{40dB} }\\\\r_{2}=(2m)\sqrt{2}\\ r_{2}=2.83m](https://tex.z-dn.net/?f=r_%7B2%7D%3D%282m%29%5Csqrt%7B%5Cfrac%7B80dB%7D%7B40dB%7D%20%7D%5C%5C%5C%5Cr_%7B2%7D%3D%282m%29%5Csqrt%7B2%7D%5C%5C%20r_%7B2%7D%3D2.83m)
at a distance of 2.83m the intensity level is 40dB
The correct choice is
A. III and IV only
according to newton's second law, force is directly proportional to the acceleration of the object and vice versa and is given as
F = ma
where F = net force on the object
m = mass of the object
a = acceleration of the object
when an unbalanced force acts on an object, the object experiences acceleration. we know that acceleration is nothing but the time rate of change of velocity. hence object experience change in velocity. The velocity can change either by a change in speed or by change in direction of motion.
Sometimes (EX:<span> HCl is a covalent substance, however, when it is dissolved it is ionized to form hydrochloric acid).</span>
Answer:
They fell at the same time.
Explanation:
Galileo was the first to discover the property of gravity, in which it makes everything fall at the same time in an airtight space. Gravity makes all objects fall and accelerate at 9.8m/s/s, regardless of weight, because the ratio between the weight of the object and the air resistance acting against it is a constant.