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Friction & Gravity

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Friction & Gravity. Forces Review. A force is a push or pull on an object. Forces have both size and direction. Forces can be balanced or unbalanced. Friction. Based on your prior knowledge, what is friction?. Friction. Friction is a force that RESISTS motion. (works against it) - PowerPoint PPT Presentation

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Page 1: Friction & Gravity
Page 2: Friction & Gravity

A force is a push or pull on an object.

Forces have both size and direction.

Forces can be balanced or unbalanced.

Page 3: Friction & Gravity

Based on your prior knowledge, what is friction?

Page 4: Friction & Gravity

Friction is a force that RESISTS motion. (works against it)

Occurs when two objects are in contact with one another.

Page 5: Friction & Gravity

What two objects are experiencing friction in these examples?› A person walking› A car driving on the street› A boat sailing on a lake› An airplane flying in the air

Page 6: Friction & Gravity

Which force represents friction in a car driving down the street?

525 N

1025 N

Page 7: Friction & Gravity

Change the surface of the objects› Rougher surface=Greater Friction

Increase the force keeping the objects in contact› Ex. Rubbing your hands together

Page 8: Friction & Gravity

Change the surface of the objects› Smoother surface=Less Friction

Decrease the force keeping the objects in contact› Ex. Rubbing your hands together

Use a lubricant (ex. Oil, grease, water)

Page 9: Friction & Gravity

Why does a surface covered in ice have less friction than a surface not covered in ice?

Think of some activities that would change if there was no friction.

Page 10: Friction & Gravity

Based on your prior knowledge and observations, what is gravity?

Page 11: Friction & Gravity

Gravity is a force that attracts objects to each other.

Every object has its own force of gravity.

Gravity PULLS objects towards the center of the object.

Page 12: Friction & Gravity

The strength of gravity depends on the objects MASS. › More MASS=More GRAVITY› Most objects are too small to exert a

detectable amount of gravity Gravity increases as you near the

center of the object. What objects gravity do we experience

the most?

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The Less MASS an object has the Less GRAVITY it exerts.

The farther away from the objects center, the less gravity exerted by that object.

Page 14: Friction & Gravity

Why do astronauts experience less gravity on the moon?

Denver is on average a mile above sea level while New Orleans is on average 100ft below sea level. At which city will you experience more gravity from the Earth?