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
Explanation:
Given
initial speed(u)=3 m/s
mass of each ball is m
Let the cue ball is moving in x direction initially
In elastic collision Energy and momentum is conserved
Let u be the initial velocity and
be the final velocity of 8 ball and cue ball respectively

The angle after which cue ball is deflected is given by

Conserving momentum in x direction


Along Y axis


substitute the value of 
we get 

To find <em>Speed </em>you divide distance by time.
Reasoning:
Displacement is the change in an object's position from the origin.
To find Acceleration you use the equation a=v^2/r
To find Velocity you divide the distance by the time it takes to travel that distance, then you add your direction to it.
<em>To find speed you use distance is over time</em>
Answer:
A
Explanation:
hydrostatic pressure, P=hρg,
where 'h' is the ht of the liq column and ρ is the density of the liquid and 'g' is the effective acceleration, but as far as hydroSTATICS is concerned, g stands for the acceleration due to gravity