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Why doesn't a ball roll on forever after being kicked at a soccer game

User Vikram R
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6.5k points

1 Answer

3 votes
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.

User Kalpesh Kundanani
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6.3k points