Answer: potential energy but no kinetic energy
Explanation:
Since the rock is stationary, velocity is zero, therefore no kinetic energy,but there's potential energy because the rock is at rest,
Sound level at distance of 15 m is given as 20 dB
so intensity at this distance is given as
![L = 10 Log\frac{I}{I_0}](https://tex.z-dn.net/?f=L%20%3D%2010%20Log%5Cfrac%7BI%7D%7BI_0%7D)
![20 = 10 Log{I}{10^{-12}}](https://tex.z-dn.net/?f=20%20%3D%2010%20Log%7BI%7D%7B10%5E%7B-12%7D%7D)
![I_1 = 10^{-10}W/m^2](https://tex.z-dn.net/?f=I_1%20%3D%2010%5E%7B-10%7DW%2Fm%5E2)
now if we move closer to some some distance the sound level is now 50 dB
now the intensity is given as
![L = 10 Log\frac{I}{I_0}](https://tex.z-dn.net/?f=L%20%3D%2010%20Log%5Cfrac%7BI%7D%7BI_0%7D)
![50 = 10Log\frac{I}{10^{-12}}](https://tex.z-dn.net/?f=50%20%3D%2010Log%5Cfrac%7BI%7D%7B10%5E%7B-12%7D%7D)
![I_2 = 10^{-7}W/m^2](https://tex.z-dn.net/?f=I_2%20%3D%2010%5E%7B-7%7DW%2Fm%5E2)
now we know that
![\frac{I_1}{I_2} = \frac{r_2^2}{r_1^2}](https://tex.z-dn.net/?f=%5Cfrac%7BI_1%7D%7BI_2%7D%20%3D%20%5Cfrac%7Br_2%5E2%7D%7Br_1%5E2%7D)
![\frac{10^{-10}}{10^{-7}} = \frac{r_2^2}{15^2}](https://tex.z-dn.net/?f=%5Cfrac%7B10%5E%7B-10%7D%7D%7B10%5E%7B-7%7D%7D%20%3D%20%5Cfrac%7Br_2%5E2%7D%7B15%5E2%7D)
![r_2 = 47 cm](https://tex.z-dn.net/?f=r_2%20%3D%2047%20cm)
so now the distance from friend must be 47 cm
Convection Current
This happens when there is a noteworthy contrast in temperature between two sections of a liquid. At the point when this temperature distinction exists, hot liquids rise and cool liquids sink, and after that streams, or developments, are made in the liquid
The answers to your questions are as written below:
- The objects that represents a negatively charged particle is : Image B
- The object that represents a positively charged molecule is : Image A
- The object that represents an uncharged molecule is : Image C
- The object the will not move when in an electric fied is : Image C
<h3>Different types of charges molecules</h3>
A negatively charged molecule move inwards when placed in an electric field while positively charged molecule placed in a electric field will move outwards the electric field.
A neutral/uncharged molecule will remains still when placd in an elctric field due to the absence of charges.
Hence we can concude that the answers to your questions are as listed above.
Learn more about electric charges :brainly.com/question/857179
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attached below is the missing image
It’s really C of the most mataboliza