©Weston, 2009

Motion! Whoa, cool motion, man! I can do that…

Motion!

Ouch! Oooh! Tough one, Fred! Now, on to REAL motions, not wannabe Matrix ones…

#1 Changing your Position on Earth Let’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 mile drive. The blue line, however, is a couple thousand more. The point is, the total amount you drove is your distance traveled.

#2 Distance Distance is the total amount traveled, measured by some unit. Notes – Motion I.Distance – the total amount traveled, measured by some unit. ex: 45.3 kilometers or 3 ft. Some common units for measuring distance are feet, 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 Offer I’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 called displacement. Yeah. That. And never take the bet of a crusty ol’ coach. START The distance Fred traveled was quite a long way. We’ll trace it 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”? How do you determine or measure speed? These are all questions that can be answered with 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 was Fred going? Speed has everything to do with distance and time! In fact, speed is the distance traveled divided by time, measured in distance unit per time unit. 50 meters -:- 5 seconds = 10 meters per second. 50 meters -:- 25 seconds = 2 meters per second.

#10 Average Speed Was 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 going slowly, got going faster, faster, faster, and was flying at the finish line. So, when we say that he covered the 50 meters in 5 seconds, for a speed of 10 m/s, we are really talking 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 brief moment, and he was likely going faster than 10 m/s near the end. But like your grades, the AVERAGE speed gives a total, overall look at performance. Let’s write this.

#11 Speed & Average Speed 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. 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 it really mean when you’re driving down I-35 at “65 miles per hour”? It means, that if it’s 1:30, then at 2:30 you will be 65 miles down the highway, nearing the Red River if you’re heading north or more than halfway to Waco if you’re going south.

#12 Velocity Velocity 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’t give 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 Indianapolis to watch a famous car race! (He’s hoping to get some tips for racing).

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

#14 Acceleration Whenever Fred hops in his race car, he can glance down and check out the brake and gas pedals. He knows that the gas pedal is often called the “accelerator.” That makes sense to Joe, because pressing the gas speeds up his car, and speeding up is accelerating. But did you know that the brake pedal is also an accelerator, though nobody calls 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, slowing down, or even turning/changing directions. Speeding Up Slowing Down Changing Direction

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. 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 IV.Velocity – speed in a specific direction ex: 35 meters per second south V.Acceleration – any change in motion ex: speeding up, slowing down, turning So, Fred has passed racing class and has learned a little about motion along the way. Now it’s up to YOU to pass science class by using these motion notes to help you understand these things.

#16 And That’s…