ForceA push or pull that has a size and a direction.

Makes objects speed up, slow down, or change direction.

OR

The greater the force, the greater the change in motion

will be.

The larger the object, the less effect the force will have on the

object.

Work

The use of a force to move an object.

The tree doesn’t move, so the eagle must have moved.

Inertia Measures an object’s tendency to

resist changing its motion.

Inertia depends on the amount of mass an object has.

More Mass = More Inertia

Less Mass = Less Inertia

Unless acted upon by a force, objects in motion tend to stay in motion and objects at rest

remain at rest.

Sir Isaac Newton

MotionWhen an object

changes position in relation to a reference point over a period of

time.

Balanced ForcesForces that cancel each other out because they

are equal and acting in opposite directions.

The scale doesn’t move because it is balanced. Because

balanced forces cancel each other

out, there is

NO MOVEMENT!

Unbalanced ForcesUnequal forces that do not cancel

each other out.

The scale moves because it is unbalanced.

Because unbalanced forces do not cancel

each other out,

there IS

MOVEMENT!

Friction

Force that resists motion between two touching surfaces.

Friction between your shoes and the skateboard keeps you from

sliding off as you slow down.

Friction creates heat!

If there were no friction, it would be easy to pull or push

large, heavy objects across the floor.

If there were no friction, you would not be able to walk! Your shoes would not grip the ground

and you would slide.

Without friction you would not even be able to pick anything up, because you would not be

able to grip the object. It would slip out of your hands!

To get the most out of friction, we even wear special shoes like baseball cleats, soccer cleats,

basketball shoes and track shoes.

Friction wears objects down. This is why the bottoms of your

shoes slowly disappear and why your parents have to buy new

tires for the car.

Gravity

Gravity is the pull that all objects with

mass exert on other matter.

Comparison Map

friction gravityforces

causes moveme

nt

produces heat

rubbing hands

together

tires on cement

person coming down

a slide

person falling

earth holding

the moon

apple falling