Answer:
6.9%
Explanation:
We are given that
Distance between Earth and Moon=d=
m
Radius of Earth=r=![6.37\times 10^6 m](https://tex.z-dn.net/?f=6.37%5Ctimes%2010%5E6%20m)
a.Initially gravitational pull
.....(1)
After changing
Gravitational pull
.....(2)
Equation (2) divided by equation (1)
![\frac{F'}{F}=\frac{(r+d)^2}{(d-r)^2}](https://tex.z-dn.net/?f=%5Cfrac%7BF%27%7D%7BF%7D%3D%5Cfrac%7B%28r%2Bd%29%5E2%7D%7B%28d-r%29%5E2%7D)
![\frac{F'}{F}=\frac{(3.82\times 10^8+6.37\times 10^6)^2}{(3.82\times 10^8-6.37\times 10^6)^2}=1.069](https://tex.z-dn.net/?f=%5Cfrac%7BF%27%7D%7BF%7D%3D%5Cfrac%7B%283.82%5Ctimes%2010%5E8%2B6.37%5Ctimes%2010%5E6%29%5E2%7D%7B%283.82%5Ctimes%2010%5E8-6.37%5Ctimes%2010%5E6%29%5E2%7D%3D1.069)
Increases in gravitational pull=
%
Answer:
A. Underground coal mining is dangerous because of possible tunnel collapse and possible methane gas explosions.
Explanation:
Dangers of underground coal mining include asphyxiation, methane gas poisoning, tunnel collapse and explosions of methane gas, a highly flammable gas. Methane explosions occur since this gas is a byproduct of coal. This explosion can cause tunnel collapse.
Answer:
0.6
Explanation:
Given that :
Radius, R = 7m
Period, T = 6.9s
The Coefficient of static friction, μs can be obtained using the relation :
μs = v² / 2gR
Recall, v = 2πR/T
μs becomes ;
μs = (2πR/T)² / 2gR
μs = (4π²R² / T²) ÷ 2gR
μs = (4π²R² / T²) * 1/ 2gR
μs = 4π²R / T²g
μs = 4π²*7 / 6.9^2 * 9.8
μs = 28π² / 466.578
μs = 276.34892 / 466.578
μs = 0.5922887
μs = 0.6
You have a few choices:
-- Take it out of Earth's atmosphere.
-- Put it in a tank where you pumped all the air out of it.
You can put whatever you want back in the tank, just
as long as there's no oxygen in there.
-- Besides oxygen, rusting also needs water. The humidity
(water vapor) in the air is enough to do it. So if you can
keep the air totally, totally dry around the iron, then the
oxygen alone won't make it rust.
-- All these choices do the same thing: Make sure that
oxygen and water vapor can't reach the iron. The easy
way to do that is to paint or spray something onto the
surface of the iron that keeps the air away from it.
Answer:
I don't know I'm sorry I will tell you another answer asks me