Distance/Displacement What’s the difference?

Distance/DisplacementDistance/DisplacementWhat’s the difference?What’s the difference?

Distance - how far in actual travel. Scalar – it has magnitude - ex: 300 meters around the track.

Just like a car’s odometer, it keeps track of how far the car has traveled

Distance/DisplacementDistance/DisplacementWhat’s the difference?What’s the difference?

Displacement – distance between two points. Vector quantity– it has magnitude and direction. 20 miles Northeast

If a car goes 300 meters around the track and winds up where it started, the displacement is 0…..there is no distance between the beginning and ending point..

• Each car travels a distance of 2.5 meters from start to finish

• From start to finish, the car has a displacement of 0 meters

Start/Finish Line

DISTANCE vs. DISTANCE vs. DISPLACEMENTDISPLACEMENT

http://physics.info/displacement/desk-animated.html

Distance is total amount traveled (scalar quantity) while displacement is the description of the direct path between points using direction (vector quantity)

Let’s PracticeLet’s Practice Josselyn rides her bike to the nearest Verizon

store to get her new phone. The store is 2 km to the north. She then rides 1 km to the south to show her new phone off to Karla.

What distance did she travel? What is her displacement?

Let’s PracticeLet’s Practice James has a hot date with Chanice and picks

her up in his car. He takes her dancing at the club which is 15km away. After dancing, they drive back past her house and grab some food at the IHOP, 5 km to the west of her house.

What distance did they travel? What is their displacement?

LetLet

MOTION, SPEED & VELOCITYMOTION, SPEED & VELOCITY

Are these people moving? Are these people moving?

MotionMotion

A change in position relative to A change in position relative to a frame of referencea frame of reference

Frame of ReferenceFrame of Reference

Your perspective Your perspective or viewpoint to or viewpoint to determine if an determine if an object is movingobject is moving

How can you tell something How can you tell something is in motion?is in motion?

It changes position relative to a It changes position relative to a fixed pointfixed point

SPEEDSPEED

Fastest man in the world….who is this?Fastest man in the world….who is this? Usain “Lightening” BoltUsain “Lightening” Bolt

Constant SpeedConstant Speed

Changing equal amounts of Changing equal amounts of distance in equal units of timedistance in equal units of time

Speed = distance/timeSpeed = distance/time

What does Constant Speed What does Constant Speed look like?look like?

Motion Map: If I was eating ice cream and it Motion Map: If I was eating ice cream and it was dripping on the ground every second….was dripping on the ground every second….

VelocityVelocity

Speed plus a directionSpeed plus a direction

Example: 30 km/hr Example: 30 km/hr northnorth

Constant Velocity Lab

Groups of no more than 4 people. Everyone has a job. Write it on your sheet.

I should be able to come by and see who should be doing what. Timer Car start Car catcher Marker

Lab Report:Lab Report: Title: Constant Velocity LabTitle: Constant Velocity Lab Names of group membersNames of group members Purpose: Purpose: To describe constant motionTo describe constant motion Materials: Materials: Methods (Methods (in full sentencesin full sentences)) Data (Data (in tablein table – time & distance) – time & distance) Analysis (graph your Analysis (graph your averageaverage distance, distance, do do

a line of best fita line of best fit. Compare two points along . Compare two points along the line to get the car’s velocity)the line to get the car’s velocity)

Data Table

Time (s) Distance (cm) Trial 1

Distance (cm) Trial 2

Distance (cm) Trial 3

Average Distance (cm)

0 0 0 0 (0+0+0)/3 = 0

1

2

3

4

5

6…

Ave

rag

eD

ista

nce

(cm

)

Time (seconds)