The ball has to push things out of its way in order to keep going.
For example:
-- billions of air molecules
-- hundreds of blades of grass .
-- To push something out of its way, the ball exerts a force against the
obstacle, and pushes it some distance.
-- A force acting through a distance is 'work', and that means 'energy'.
-- The ball has a certain amount of energy ... the amount you gave it
when you kicked it. It gives every air molecule and blade of grass a
little bit of energy, so the ball has less and less as it goes along.
-- Eventually, it has no more energy to use to push things out of the way.
No energy means no motion, so it stops.
-- If it were in space where there are no air molecules and no grass,
it would go on forever.
Answer:
In a normal kettle the heating element is at the bottom so the water it heats rises. It then pushes the cooler water at the top downwards so that too can be heated.
We can use the equation of motion:
s = ut + 1/2 x at²
Both the velocity and acceleration are downwards so we'll consider the downward direction positive
30 = 8t + 4.91t²
4.91t² + 8t - 30 = 0
Solving the quadratic:
t = 1.79 s; t = -3.42 s
Negative time is not possible so second value discarded. Time taken = 1.79 seconds
Answer:
Width of the slit will be equal to 1.47 mm
Explanation:
We have given wavelength of the light 
Distance D = 8 m
Distance between first minimum dark fringe and the central maximum is 2 mm
So 
We have to find the width of the slit
For the first order wavelength is equal to
, here a width of slit
So 
So width of the slit will be equal to 1.47 mm