Motion Makes the World Go

8/21/2019 Motion Makes the World Go

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Motionmakes the world go 'round. Motion makes themoon go 'round too. In fact, motion makes lots of things go. When we think of motion we often

think of cars, bicycles, kids running, basketballs bouncing and airplanes flying. But motion is so

much more. Motion is important to our lives and impacts so many things that we do. Motion isthe changing of position or location. But motion requires a force to cause that change. et's learn

about force and motion and the effects of these physical laws in our world.

What is Force?

!orce is "ust a fancy word for pushing or pulling. If I push on

something or pull on it, then I am applying a force to it. !orce makes things move or, moreaccurately, makes things change their motion. #wo natural forces that we have e$perienced are

the force of gravityand magnetic forces.

#hese two forces act at a distance and do not require direct contact between the ob"ects to

function. %ravity produces a force that pulls ob"ects towards each other, like a person towards
http://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#motionhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#gravityhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#gravityhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#magnetic%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#gravityhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#magnetic%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#motion


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the ground. It is the force that keeps the &arth revolving around the sun and it's what pulls you

toward the ground when you trip.

ee ()*'s site on %ravity.

Magnetism produces a force that can either pull opposite ends of

two magnets together or push the matching ends apart. + magnet also attractsob"ects made of

metal.

Types Of Contact Forces

#here are kinds of forces which act on ob"ects when they come into contact with one another.

-emember, a force is either a push or pull. #he are

normal force applied force

frictional force

tension force

spring force

resisting force
http://idahoptv.org/dialogue4kids/season12/gravity/index.cfmhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#attracthttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#attracthttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#attracthttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#normal%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#applied%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#frictional%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#tension%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#spring%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#resisting%20forcehttp://idahoptv.org/dialogue4kids/season12/gravity/index.cfmhttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#attracthttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#normal%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#applied%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#frictional%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#tension%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#spring%20forcehttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#resisting%20force


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et's investigate how these forces can be seen in our lives.

Normal Force

+ book resting on a table has the force of gravity pulling it toward

the &arth. But the book is not moving or accelerating, so there must be opposing forces acting onthe book. #his force is caused by the table and is known as the normal force. /ou can 0see0 the

normal force in some situations. If you place a thin piece of wood or plastic 1a ruler works2 so

that it is supported by both ends 1by books perhaps2 and place a small heavy ob"ect in the center,the piece of wood will bend. 3f course it wants to straighten out so it e$erts an upward force on

the ob"ect. #his upward force is the normal force. /ou can feel the force yourself if you push

down in the center of the piece of wood. #he harder you push, the more the wood bends and theharder it pushes back.

&$periment with this concept by trying one of these paper bridge e$periments from 433MorBuilding Big5
http://www-tc.pbskids.org/zoom/printables/activities/pdfs/paperbridge.pdfhttp://www.pbs.org/wgbh/buildingbig/educator/act_paper_ei.htmlhttp://www-tc.pbskids.org/zoom/printables/activities/pdfs/paperbridge.pdfhttp://www.pbs.org/wgbh/buildingbig/educator/act_paper_ei.html


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Applied Force

+pplied force refers to a force that is applied to an ob"ect such as when a person moves a pieceof furniture across the room or pushes a button on the remote control. + force is applied.

Frictional Force

!rictional force is the force caused by two surfaces that come into contact with each other.

!riction can be helpful as in the friction that allows a person to walk across the ground without

sliding or it can be destructive such as the friction of moving parts in a motor that rub togetherover long periods of time.

Tension Force

#ension force is the force applied to a cable or wire that is anchored on opposite ends to

opposing walls or other ob"ects. #his causes a force that pulls equally in both directions.


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Spring Force

#he spring force is the force created by a compressed or stretched spring. (epending upon howthe spring is attached, it can pull or push in order to create a force.

Resisting Forces

-esisting forces like air resistance or friction change motion.

Whether the forces actually stop or slow something depends upon your point of view. +ir

friction makes a leaf travel along in the wind. When you pick up a pencil, it's friction with yourfingers that gets the pencil in motion. In each case, the friction makes the two things 1like the air

and the leaf2 move together.

What is Inertia?Inertiais actually not a force at all, but rather a property that all things have due to the fact that

they have mass. #he more mass something has the more inertia it has. /ou can think of inertia as

a property that makes it hard to push something around.

What is Friction?

!riction is a force that happens when ob"ects rub against one another. ay you were pushing a

toy train across the floor. It doesn't take much effort or force, because the toy is light. 6ow say

you try to push a real train. /ou probably can't do it because the force of friction between thetrain and the ground is more intense. #he heavier the ob"ect, the stronger the force of friction.
http://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#inertiahttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#masshttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#inertiahttp://idahoptv.org/dialogue4kids/season12/force_and_motion/glossary.cfm#mass


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Velocity

7elocityis the speed of an ob"ect in one direction. If an ob"ect turns a corner, it changes its

velocity because it is no longer moving in its original direction.

Newtons !aws of "otion

ome consider ir Isaac 6ewton to be the greatest&nglish mathematician of his time and perhaps oneof the greatest scientists the world has known.

+ccording to a story, 6ewton saw an apple fall to the

ground and he figured out that the same force which

caused the apple to fall also governed the motion ofthe Moon and the planets. In 89: 6ewton published

his three laws of motion in the 0;rincipia

Mathematica ;hilosophiae 6aturalis.0


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6ewton's first law of motion states + body in motion tends to remain in motion, a body at rest

tend to remain at rest unless acted on by an outside force.

o, if an ob"ect is moving = its inertia 1mass2 will tend to keep it in motion, and if something is atrest, its inertia will tend to keep it at rest.

!rom the %oddard pace >enter learn more about6ewton's !irst aw.

+dditional ideas.

Newtons

Second

!aw

6ewton's second law of motion states that a force, acting on an ob"ect, will change its velocity bychanging either its speed or its direction or both.

If your basketball goes rolling into the street and is hit by a bike, either the ball will change

direction or its speed or both. It will also be true of the bike.

!rom the %oddard pace >enter learn more about6ewton's econd aw.

+dditional ideas.
http://swift.sonoma.edu/education/newton/newton_1/html/newton1.htmlhttp://swift.sonoma.edu/education/newton/newton_1/index.htmlhttp://swift.sonoma.edu/education/newton/newton_2/html/newton1.htmlhttp://swift.sonoma.edu/education/newton/newton_2/index.htmlhttp://swift.sonoma.edu/education/newton/newton_1/html/newton1.htmlhttp://swift.sonoma.edu/education/newton/newton_1/index.htmlhttp://swift.sonoma.edu/education/newton/newton_2/html/newton1.htmlhttp://swift.sonoma.edu/education/newton/newton_2/index.html


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Newtons

Third

!aw

#he third law is probably the best known of 6ewton's laws. It states that for every force and

action, there is an equal and opposite reaction.

#his is what causes a cannon to recoil when it fires. #he 'kick' from the firing of the ammunition

is what makes the cannon "ump backwards.

!rom the %oddard pace >enter learn more about6ewton's #hird aw.

#RA$%S & ' (

IN%RTIA

W)AT WI!! *O+ $O?,

Inertia makes things difficult to

stop as well as hard to get started.

/ou will conduct two fun

demonstrations to illustrate these

principles. /ou'll learn about ir

Isaac 6ewton and his first ? laws

of motion.

(o you know how to tell a

hardboiled from a raw eggwithout cracking it open@ #his

e$periment will teach you how.

/ou also will learn that inertia is

the science principle behind why

we wear seat belts.

"AT%RIA!S,

A 8 -aw &gg In hellA 8 ardboardA Brick 3r


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ST%.S TO FO!!OW,

$emonstration /,

pin an uncooked egg on its

end in the rimmed pan.#ouch it lightly with your

finger. +s soon as it stops,

take your finger away.

3bserve what happens.

When you touch the egg,you stop the shell from

spinning, but inertia keeps

the egg white and yolk

moving. When you remove

your finger, the moving

contents make the egg start

spinning again.

#ry the demonstration again

with the hardboiled egg.

What happens when you

stop the egg, then let it go@

ince the egg is hardboiled,

all the contents move

together. We call this a rigid

body. When the shell is

stopped, so are the contents,

and the egg remains

stopped. #he contents of the

egg have no more inertia.

inclined plane. ;lace the

brick at the edge on the

table. #his will hold the

board in place as well as

form a barrier for the

wagon. ;ut the blocks in the

wagon and hold the wagon

at the top of the board.

-elease the wagon and let itroll down the board.

3bserve what happens

when the wagon hits the

barrier. #he wagon stops,

but the blocks inside

continue to move. #he

inertia of the blocks causes

them to fly out of the wagon

and over the barrier.
http://www.swe.org/iac/images/Inertia2large.jpghttp://www.swe.org/iac/images/Inertia1large.jpghttp://www.swe.org/iac/images/Hardboiled_2.movhttp://www.swe.org/iac/images/Softboiled_2.mov


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http://www.physicsclassroom.com/class/momentum/Lesson-1/Momentum

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Motion Makes the World Go