Group 0 - they are called the NOBLE GASES
(as they're very unreactive) because...
ALL of their atoms are full.
Example : Helium contains 2 electrons so it's outer shell is full
Force decreases as distance increases
Answer: 
Explanation:
The <u>centripetal acceleration</u> 
of an object moving in a uniform circular path is given by the following equation:
(1)
Where:
is the tangential velocity
is the radius of the circle
On the other hand, the tangential velocity is expressed as:
(2)
Where 
is the angular velocity, which can be found knowing the child makes 5 revolutions in 13.4s:
(3)
Substituting (3) in (2):
(4)
(5)
Substituting (5) in (1):
(6)
Finally:
According to the internet over 2% of earths fresh water is unavailable: locked up in glaciers, polar ice caps, atmosphere, and soil.
