When acceleration is constant, the average velocity is given by
where 
and 
are the final and initial velocities, respectively. By definition, we also have that the average velocity is given by
where 
are the final/initial displacements, and 
are the final/initial times, respectively.
Take the car's starting position to be at 
. Then
So we have
You also could have first found the acceleration using the equation
then solve for 
via
but that would have involved a bit more work, and it turns out we didn't need to know the precise value of 
anyway.
<em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>:</em><em>)</em>
V^2=u^2 +2aS
U is found first by considering that first 8 secs and using v=u+at. {different v and u though}
V=-u+gt.
Magnitude of u = magnitude of v if there is no resistance ( because the conservation of energy says the k. E. must be the same when it passes you as when it left your hand).... up is negative here, down is positive.
V+v=gt
2v= g x 8
V=4xg.= the initial velocity for the next calculation
V^2=(4g)^2+(2xgx21)
So v can be calculated.
Celina should perform the following method to get pure water:
Boil the water in a pan, as the water boils it changes into gas (water vapours) these vapours should be cooled down through the process of condensation which changes gas into liquid form, Through this process germs would be killed due to high temperature and the salt will remain in the pan as salt has higher boiling point than water,
A spinning top is the answer
