Speed and Acceleration Measuring motion Measuring Distance Meter

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Speed and Acceleration Measuring motion

Speed and Acceleration Measuring motion

Measuring Distance ¡ Meter – international unit for measuring distance. 1 mm = 50

Measuring Distance ¡ Meter – international unit for measuring distance. 1 mm = 50 m

Calculating Speed ¡ Speed (S) = distance traveled (d) / the amount of time

Calculating Speed ¡ Speed (S) = distance traveled (d) / the amount of time it took (t). S = d/t

Units for speed ¡ Depends, but will always be a distance unit / a

Units for speed ¡ Depends, but will always be a distance unit / a time unit l l Ex. Cars: mi. /h Jets: km/h Snails: cm/s Falling objects: m/s

Calculating speed S = d/t If I travel 100 kilometers in one hour then

Calculating speed S = d/t If I travel 100 kilometers in one hour then I have a speed of… ¡ 100 km/h ¡ If I travel 1 meter in 1 second then I have a speed of…. ¡ 1 m/s ¡

Average speed ¡ Speed is usually NOT CONSTANT l l ¡ Ex. Cars stop

Average speed ¡ Speed is usually NOT CONSTANT l l ¡ Ex. Cars stop and go regularly Runners go slower uphill than downhill Average speed = total distance traveled/total time it took.

Calculating Average Speed ¡ ¡ It took me 1 hour to go 40 km

Calculating Average Speed ¡ ¡ It took me 1 hour to go 40 km on the highway. Then it took me 2 more hours to go 20 km using the streets. Total Distance: l ¡ Total Time: l ¡ 40 km + 20 km = 60 km 1 h + 2 h = 3 hr Ave. Speed: l total d/total t = 60 km/3 h = 20 km/h

Question ¡ I traveled 25 km in 10 minutes. How many meters have I

Question ¡ I traveled 25 km in 10 minutes. How many meters have I traveled? l l A) 25000 m B). 0112 m C). 025 m D) 2. 5 m 25 km * 1000 m/km = 25000 m

Question ¡ I ran 1000 m in 3 minutes. Then ran another 1000 m

Question ¡ I ran 1000 m in 3 minutes. Then ran another 1000 m uphill in 7 minutes. What is my average speed? A) 100 m/min B) 2000 m/min Totall. Dist. = 1000 m + 1000 m = 2000 m l C) 10 m/min Totall. Time = 3 m/min + 7 min = 10 min D) 200 l E) 20 m/min Ave speed = total dist/total time = l 2000 m/10 min = 200 m/min = D

Velocity ¡ Velocity – the SPEED and DIRECTION of an object. l Example: An

Velocity ¡ Velocity – the SPEED and DIRECTION of an object. l Example: An airplane moving North at 500 mph ¡ A missile moving towards you at 200 m/s ¡

Question ¡ ¡ What is the difference between speed and velocity? Speed is just

Question ¡ ¡ What is the difference between speed and velocity? Speed is just distance/time. Velocity includes direction as well.

Velocity Vectors The direction and magnitude (amount) of speed is represented by arrows. ¡

Velocity Vectors The direction and magnitude (amount) of speed is represented by arrows. ¡ The length represents the magnitude, and the arrow points in the direction of the speed A slow speed A faster speed ¡ ¡ In any direction the object moves

Who will win the race? LAB Today: Prelab ¡ Tomorrow: Lab (wear running shoes)

Who will win the race? LAB Today: Prelab ¡ Tomorrow: Lab (wear running shoes) ¡ Wednesday: Lab DUE ¡

Position vs. Time Graphs You can show the motion of an object using a

Position vs. Time Graphs You can show the motion of an object using a graph or ¡ Infer the motion of an object from a graph. ¡

Position vs. Time Graphs: What would it look like? For example: ¡ Walk from

Position vs. Time Graphs: What would it look like? For example: ¡ Walk from the hallway through the door to the back of the room, ¡ Stop and look at the Entry Task on the board, ¡ Then go back to pick up the hand out you forgot, then back to your seat at the back of the classroom.

Position vs. Time: 6 4 2 0 -2 -4 -6 5 sec 10 sec

Position vs. Time: 6 4 2 0 -2 -4 -6 5 sec 10 sec 15 sec 20 sec 25 sec 30 sec

Velocity vs. Time ¡ ¡ You can also represent velocity instead of position. We’ll

Velocity vs. Time ¡ ¡ You can also represent velocity instead of position. We’ll be using a simulation to help visualize and practice creating and inferring an object’s motion

Velocity vs. Time You can also determine an objects speed. What does this graph

Velocity vs. Time You can also determine an objects speed. What does this graph tell you about the person’s speed? 8 6 4 2 0 -2 -4 5 sec 10 sec 15 sec 20 sec 25 sec 30 sec

Phet Sim: Moving Man ¡ Purpose: To be able to create and read graphs

Phet Sim: Moving Man ¡ Purpose: To be able to create and read graphs to describe the motion of an object.