Answer:


Explanation:
When coefficient of friction is approximately zero then we have



here we know that

R = 30 m


now when friction coefficient is 0.30 then we have


now we have




Copper because it contains alot of electricity
Answer:
Frequency = 1,550Hz
Explanation:
To solve this we can use the equation:
(frequency = velocity/wavelength).
We are given the information that the wavelength is 22cm and the speed is 340m/s. The first step is to make sure everything is in the correct units (SI units), and to convert them if needed. The SI Units for velocity and wavelength are m/s and m respectively. This means we need to convert 22cm into meters, which we can do by dividing by 100, (as there are 100cm in a meter). 22/100 = 0.22m
Now we can substitute these values into the formula and calculate to solve:

Simplify to 3 significant figures:
f = 1,550Hz
(Which I believe is just below a G6 if you were interested)
Hope this helped!
<span>They are used to measure and map effluent and pollution discharges from factories and sewerage plants, and the movement of sand around harbours, rivers and bays. Radioactive materials used for such purposes have short half-lives and decay to background levels within days.</span>
Answer:
Explanation:
The time period of geosynchronous satellite must be equal to T .
The radius of its orbit will be ( R+ h )
orbital velocity V₀ = 
Time period T = 2π( R + h ) / V₀
= 2π( R + h ) x 
= R +h
h =
- R.