©weston, 2009 motion! whoa, cool motion, man! i can do that…

©Weston, 2009

Motion!

Whoa, cool motion, man!I can do that…

Motion!

Motion!

Ouch!

Oooh! Tough one, Fred!

Now, on to REAL motions,

not wannabe Matrix ones…

#1 Changing your Position on EarthLet’s say you drove from…

The great state of Texas

…to…

the somewhat acceptable state of Montana.

…how far did you drive?

Well, the green line is probably a 1000+ mile drive. The blue line, however, is a couplethousand more. The point is, the total amount you drove is your distance traveled.

#2 DistanceDistance is the total amount traveled, measured by some unit.

Notes – MotionI. Distance – the total amount traveled,

measured by some unit.ex: 45.3 kilometers or 3 ft.

Some common units for measuring distance arefeet, miles, kilometers, inches, etc. In other words,distance is just a length!

#3 Fred goes to Racing School

SWEET!

#4 Fred’s Coach Makes an OfferI’ll be on this tricycle and you’ll be driving the race car. If I peg you with this

tomato, you owe me lunch. I’ll even give you a

1-minute head start.

Ha!Piece of cake!

It’s a deal, coach.

#5 Here’s The Race Track

START

Fred and Coach take their positions.

#5 And He’s Off!

START

#5 Fred accelerates down the track

START

#5 Fred’s Flyin’ Now

START

Ha!What a chump.I’m gonna have

Burger King.

#5 Decelerate for the Curve

START

#5 Hit the gas again, Joe!

START

…28…29

THIRTY!

#5 Coach goes about…oh…2 feet.

START

#5 Fred is REALLY smokin’ Coach!

START

*yawn*

#5 Umm…Fred?

START

Uh oh.

#5 Coach Takes Aim…

START

#5 …and launches…

START

#5 INCOMING!

START

#5 Dang.

START

Oh poop.

Hmmm…Taco Bell?

Whataburger?

#6 And Fred’s Lesson from All This?…that there’s a BIG difference between distance traveled and a term calleddisplacement.

Yeah. That.

And never take the bet of a crusty ol’

coach.

START

The distance Fred traveled was quite a long way. We’ll traceit in blue.

But what about the distance Fred was (when he got splattered) from the starting point?We’ll put that one in red. This is what we mean when we say “displacement.”

#7 Write It!Notes – Motion

I. Distance – the total amount traveled,measured by some unit.

ex: 45.3 km or 3 ft.II. Displacement – the direction and distance

between the starting and ending points.

#8 Speed!What does “speed” mean to you? What does it mean to be “fast” or “slow”? Howdo you determine or measure speed? These are all questions that can be answeredwith a little help from Fred.

Fred is going to race this turtle.But before they do, here’s your task:

Describe the speeds that they will reach,but you HAVE to use the word “distance”in your description.

Yeah…Fred will go a greater distance than the turtle…in the same amount of time.

#9 So, what is speed?Fred hits the finish line, 50 meters away, in 5 seconds.

The turtle travels the same 50 meters in 25 seconds.

So, what was Joe’s speed? What was the turtle’s speed? How much faster wasFred going? Speed has everything to do with distance and time!

In fact, speed is the distance traveled divided by time, measured in distance unit pertime unit.

50 meters -:- 5 seconds = 10 meters per second.

50 meters -:- 25 seconds = 2 meters per second.

#10 Average SpeedWas Fred’s car traveling the exact same speed from start to finish in his race?

No, of course not. He was at a standstill at the start of the race, then started goingslowly, got going faster, faster, faster, and was flying at the finish line.

So, when we say that he covered the 50 metersin 5 seconds, for a speed of 10 m/s, we are reallytalking about Fred’s AVERAGE speed in the race.

At some points he was going slower than 10 m/s,he might have been going exactly 10 m/s for a briefmoment, and he was likely going faster than 10 m/snear the end. But like your grades, the AVERAGEspeed gives a total, overall look at performance.

Let’s write this.

#11 Speed & Average SpeedNotes – Motion



between the starting and ending points.III. Speed – distance traveled divided by time,

measured in distance units per time units.ex: biking 40 miles in 2 hours = 20 mph

A. Average speed – total distance -:-total time

ex: driving 15 miles in 10 minutes= 1.5 miles per minute

So, what does itreally meanwhen you’redriving downI-35 at “65 milesper hour”?

It means, that ifit’s 1:30, then at2:30 you will be65 miles down thehighway, nearingthe Red River ifyou’re headingnorth or more thanhalfway to Wacoif you’re goingsouth.

#12 VelocityVelocity is very similar to speed, but with one important difference. Let’s see.

Fred gets on a plane at DFW airport. The plane goes 400 miles per hour for 2 hours.That means he’s gone 800 miles from Dallas/Ft. Worth. So, where is he?

Atlanta?

Chicago?

Denver?

Mexico?

Yeah kid. Who knows?

#13 Velocity, contd.So just telling you the speed that Fred’s plane went (and even how long he flew) doesn’tgive you as much information as you’d like.

You also need to know Fred’s direction of travel.

Fred’s plane went 400 mph for 2 hours (800 total miles) northeast from Dallas.

Fred’s in Indianapolisto watch a famouscar race! (He’s hoping to getsome tips for racing).



between the starting and ending points.III. Speed – distance traveled divided by time,

measured in distance units per time units.ex: biking 40 miles in 2 hours = 20 mph



IV. Velocity – speed in a specific directionex: south at 35 meters per second

#14 AccelerationWhenever Fred hops in his race car, he can glance down and check out the brake andgas pedals.

He knows that the gas pedal is oftencalled the “accelerator.”

That makes sense to Joe, becausepressing the gas speeds up his car,and speeding up is accelerating.

But did you know that the brake pedalis also an accelerator, though nobodycalls it that?

Heck, even the steering wheel can be considered an accelerator. For real.

So, what does it mean to “accelerate”then?

#15 It can be a little confusing……but try to get the notion that accelerating only means “speeding up” out of your head.

Yes, going faster IS acceleration, but it is just one of many possibilities for acceleration.

Acceleration is really ANY change in motion, and that can mean speeding up, slowingdown, or even turning/changing directions.

Speeding Up

Slowing Down

Changing Direction



IV. Velocity – speed in a specific directionex: 35 meters per second south

V. Acceleration – any change in motionex: speeding up, slowing down, turning

So, Fred has passed racingclass and has learned a littleabout motion along the way.

Now it’s up to YOU to passscience class by using thesemotion notes to help youunderstand these things.

#16 And That’s…

©weston, 2009 motion! whoa, cool motion, man! i can do that…

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