The ForceFriction

The ForceFriction

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Will a paper clip and a tissue fall withthe same speed and force?

NO!!! The tissue floats slowly, movingfrom side to side.

The paperclip falls straight down!

But if they weigh about the same, shouldn’t the force of gravity affect them the same?

Newton was verytroubled by this!

He went all over, dropping objects to try to understand theforce of gravity!

One day, when Newton was dropping things off the leaning tower of Pisa,

he realized the answer...

The force of gravityis the same everywhere!

The objects fell with different speed and force because... ... ...

The force of gravityis the same everywhere!

...There was another force acting on some of the objects!

Newton wasso surprised!

(okay, maybe notTHIS surprised!)

The other force is called Friction.

Friction= a force that acts in theopposite direction of motion!

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The force of thefriction cancelledsome of the forceof gravity!

As the tissue started to fall, it bumped into

some air molecules!

The air made the tissue have to move around, andslowed it down!

This special kind of friction is calledair resistance!

Paper

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Larger sizedobjects run into moreair resistance, and are slowed by the friction. Small objects fall free!

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Most friction happens when two objects touch.

The more contact there is, the greaterthe magnitude of friction!

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This is why round things don’t slowdown as much when pushed:

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Rougher surfaces also cause more friction because they act like lots of speed bumps!

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This is why our skate shoes are flatwith lots of ridges!

The friction keeps us from slidingoff our skateboards!