Describing and Measuring MotionDescribing and Measuring MotionHow do you recognize motion?How do you recognize motion?

An object is in An object is in motionmotion when its when its distancedistance from from another object is another object is changingchanging

Movement Movement depends on your depends on your point of point of viewview

What is a reference What is a reference point?point?A A placeplace or object used for or object used for

comparison to determine if comparison to determine if something is in something is in motionmotion

An An objectobject is in motion if it is in motion if it changes changes positionposition relative to relative to a a referencereference point point

Determining When an Determining When an Object is in MotionObject is in Motion

Whether or not an object is in motion Whether or not an object is in motion dependsdepends on the on the reference pointreference point you choose & if the you choose & if the distance betweendistance between the object and the reference point is the object and the reference point is changingchanging..

SWBAT: Investigate, measure and describe what happens to SWBAT: Investigate, measure and describe what happens to the motion, speed ,velocity and acceleration of moving the motion, speed ,velocity and acceleration of moving objectsobjects

Negative Distance & Negative Distance & FootballFootball

Question:Question: Can a distance be negative Can a distance be negative in relationship to a reference point?in relationship to a reference point?

Football Example: Football Example: Reference pointReference point in in football (below), football (below), positive playpositive play (right), (right), negative play- sacked for a lossnegative play- sacked for a loss (bottom (bottom right)right)

Which of the following is true if you are riding your Which of the following is true if you are riding your bike past the middle school?bike past the middle school?

A.A. You are moving relative to the bike, but not the school.You are moving relative to the bike, but not the school.

B.B. You are not moving relative to the school or the bike.You are not moving relative to the school or the bike.

C.C. You are moving relative to the school, but not relative You are moving relative to the school, but not relative to the bike.to the bike.

D.D. You are moving relative to the bike and the school.You are moving relative to the bike and the school.

What is the basic unit of length?What is the basic unit of length?

The The metermeter – – a little longer a little longer than a than a yardyard

What do scientists use to measure the What do scientists use to measure the

length of an object smaller than a yard?length of an object smaller than a yard? A A centimetercentimeter – –

one hundredth of a one hundredth of a meter, so there are meter, so there are 100100 centimeters in centimeters in a a metermeter

A A millimetermillimeter – – There are There are 1,0001,000 millimeters in a millimeters in a metermeter

How do scientists measure long How do scientists measure long distances?distances?

The The kilometerkilometer – – There are There are 1,0001,000 meters meters in a kilometerin a kilometer

1mile= 1mile= 1.6km1.6km

How do scientists calculate How do scientists calculate speed?speed?

Speed – the Speed – the distancedistance the object the object travels in one unit of travels in one unit of timetimeRate – tells you the amount of Rate – tells you the amount of

somethingsomething that occurs or that occurs or changes in one unit of changes in one unit of timetime

Speed = Speed = distancedistance timetime

What is constant speed?What is constant speed?

If the If the speedspeed of of an object does an object does notnot change, change, the object is the object is traveling at a traveling at a constant constant speedspeed

What is average speed?What is average speed?Most objects do Most objects do

notnot move at move at constant constant speedsspeeds for very for very longlong

To find average To find average speed speed dividedivide the the total total distancedistance by by the total the total timetime

•Car trip

Calculating SpeedCalculating Speed How can you calculate speed? If you travel 45 km in 3 hours, How can you calculate speed? If you travel 45 km in 3 hours,

what is your average speed? what is your average speed?

Speed = change in distance/change in timeSpeed = change in distance/change in time

Instant speedInstant speed is your speed at a is your speed at a certain timecertain time..

Average speedAverage speed is your averaged speed for the ENTIRE trial, is your averaged speed for the ENTIRE trial, event, or race. event, or race.

Avg. speed = change in distance/change in timeAvg. speed = change in distance/change in time

What is Velocity?What is Velocity?SpeedSpeed in a given in a given

directiondirection

When you know the When you know the speedspeed and and directiondirection of of an objectan object’’s motion, you s motion, you know the know the velocityvelocity of the of the objectobject

Example 15 km/hour Example 15 km/hour westwardwestward

Do Now: What is the speed average speed of Do Now: What is the speed average speed of a car that traveled 75km/h in 5 hoursa car that traveled 75km/h in 5 hours

Speed= Distance/ TimeSpeed= Distance/ Time

Distance= 75km , Time =5 hours so Distance= 75km , Time =5 hours so 75km/5hrs= 15km/hr 75km/5hrs= 15km/hr

SWBAT: Investigate, measure and describe SWBAT: Investigate, measure and describe what happens to the motion, speed ,velocity what happens to the motion, speed ,velocity and acceleration of moving objectsand acceleration of moving objects

How do you graph How do you graph motion?motion?

You can show the You can show the motionmotion of an object of an object on a on a lineline graph in graph in which you plot which you plot distancedistance against against timetime

TimeTime is along the x- is along the x-axis and axis and distancedistance on the y-axison the y-axis

How do you interpret motion How do you interpret motion graphs?graphs?

A A straightstraight line indicates line indicates a a constantconstant speed speed

The The steepnesssteepness depends depends on how quickly or slowly on how quickly or slowly the object is moving the object is moving The faster the motion The faster the motion

the the steepersteeper the slope the slope

Distance Determination (from a Speed-Time Distance Determination (from a Speed-Time Graph)Graph)

How far will the object have gone in 2 seconds?How far will the object have gone in 2 seconds?

10 meters (5 m/s x 2 s)10 meters (5 m/s x 2 s)

OrOr

Determine the area under the lineDetermine the area under the line: Create a rectangle : Create a rectangle and determine its area (l x w = 2 s x 5 m/s = 10 m)and determine its area (l x w = 2 s x 5 m/s = 10 m)

SWBAT: Investigate, measure and describe what happens to SWBAT: Investigate, measure and describe what happens to the motion, speed ,velocity and acceleration of moving objectsthe motion, speed ,velocity and acceleration of moving objects

5 m/s5 m/s

1 s 2 s

SPEED (m/s)

Time (s)

Graphing Motion (Calculating speed)Graphing Motion (Calculating speed)You can show the motion of an object on a line You can show the motion of an object on a line

graph in which you plot graph in which you plot distance versus timedistance versus time. . RememberRemember: Velocity is the : Velocity is the change in change in distancedistance in a in a certain direction during a certain direction during a certain lengthcertain length of of timetime. . So, So, velocity or speed = rise/runvelocity or speed = rise/run

Speed vs. VelocitySpeed vs. Velocity

Do Now: Do Now: Mark is jogging at 6.0 mph, while Sue is also jogging at 6.0 mph. However, Mark’s Mark is jogging at 6.0 mph, while Sue is also jogging at 6.0 mph. However, Mark’s velocity is -6.0 mph while Sue’s is 6.0 mph. Why are their speeds the same, but their velocities are velocity is -6.0 mph while Sue’s is 6.0 mph. Why are their speeds the same, but their velocities are different?different?

SWBAT: Investigate, measure and describe what happens to the motion, speed ,velocity and SWBAT: Investigate, measure and describe what happens to the motion, speed ,velocity and acceleration of moving objectsacceleration of moving objects

Goal:Goal: Determine the difference between SPEED and VELOCITY. Determine the difference between SPEED and VELOCITY.

Hypothesis:Hypothesis: What do you think is the difference between speed and velocity? What do you think is the difference between speed and velocity?

Results:Results: Organize the VELOCITIES FOR EACH PERSON in a DATA TABLE. Organize the VELOCITIES FOR EACH PERSON in a DATA TABLE.

Speed vs. Velocity Speed vs. Velocity ExperimentExperiment

•Were there any Were there any negative velocitiesnegative velocities? Why is this the case?? Why is this the case? Is Is velocity just speed? If not, what else is factored in to velocity? velocity just speed? If not, what else is factored in to velocity? Hint- Hint- Think about when your velocity was Think about when your velocity was negativenegative relative to the relative to the motion sensor, and keep in mind that speed is NEVER negative.motion sensor, and keep in mind that speed is NEVER negative.

Scenario:Scenario: Mark is jogging at a speed of 6.0 mph, while Sue is also Mark is jogging at a speed of 6.0 mph, while Sue is also jogging at a speed of 6.0 mph. However, Mark’s velocity is -6.0 mph jogging at a speed of 6.0 mph. However, Mark’s velocity is -6.0 mph while Sue’s is 6.0 mph. Why are their speeds the same, but their while Sue’s is 6.0 mph. Why are their speeds the same, but their velocities are different?velocities are different?

Velocity = speed + direction relative to a reference pointVelocity = speed + direction relative to a reference point

So, So, MarkMark was going was going just as fastjust as fast as Sue, but in the as Sue, but in the opposite opposite direction.direction.

Peregrine Falcons can dive at speeds up to 242 mph.

What is Acceleration?What is Acceleration?The The raterate at which at which

velocityvelocity changes changes

In science, In science, acceleration refers acceleration refers to:to:increasingincreasing speed speeddecreasingdecreasing speed speedchanging changing directiondirection

How do you calculate How do you calculate acceleration?acceleration?

To determine the acceleration rate To determine the acceleration rate of an object, you must calculate of an object, you must calculate the the changechange in velocity during each in velocity during each unit of unit of timetime

Acceleration = Acceleration = Final velocity – Starting Final velocity – Starting velocityvelocity

TimeTime

Calculating AccelerationCalculating Acceleration What does it mean if a car What does it mean if a car acceleratesaccelerates? Have you ever heard of a car ? Have you ever heard of a car

that can go that can go 0 to 60 mph0 to 60 mph in about in about 6 seconds6 seconds? (Just like mine). What ? (Just like mine). What about when a car about when a car deceleratesdecelerates? ?

To determine the To determine the accelerationacceleration of an object moving in a straight line, you of an object moving in a straight line, you must calculate the must calculate the change in velocity per unit of timechange in velocity per unit of time

Average Acceleration = (final velocity – starting velocity)/timeAverage Acceleration = (final velocity – starting velocity)/time

Acceleration- The rate at which velocity changesAcceleration- The rate at which velocity changes

Graphing AccelerationGraphing Acceleration You can use both a You can use both a speed-versus-timespeed-versus-time

graph and a graph and a distance-versus-timedistance-versus-time graph graph to analyze the motion of an to analyze the motion of an accelerating object.accelerating object.

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Calculating AccelerationCalculating Acceleration As a roller-coaster car starts down a slope, its speed is 4 As a roller-coaster car starts down a slope, its speed is 4

m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. What is its average acceleration?What is its average acceleration?

Read and UnderstandRead and Understand

What information have you been given?What information have you been given?

Initial speed = Initial speed = 4 m/s4 m/s

Final Speed = Final Speed = 22 m/s22 m/s

Time = Time = 3 s3 s

Calculating AccelerationCalculating Acceleration As a roller-coaster car starts down a slope, its speed is 4 As a roller-coaster car starts down a slope, its speed is 4

m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. What is its average acceleration?What is its average acceleration?

Plan and SolvePlan and Solve

What quantity are you trying to calculate?What quantity are you trying to calculate?

The average acceleration of the roller-coaster car = __The average acceleration of the roller-coaster car = __

What formula contains the given quantities and the What formula contains the given quantities and the unknown quantity?unknown quantity?

Acceleration = (Acceleration = (Final speedFinal speed – – Initial speedInitial speed)/)/TimeTime

Perform the calculation.Perform the calculation.

Acceleration = (Acceleration = (22 m/s22 m/s – – 4 m/s4 m/s)/)/3 s3 s = 18 m/s/ = 18 m/s/33 ss

Acceleration = 6 m/sAcceleration = 6 m/s22

The roller-coaster carThe roller-coaster car’’s average acceleration is 6 m/ss average acceleration is 6 m/s22..

This is a This is a positive accelerationpositive acceleration (speeding up).(speeding up).

Calculating AccelerationCalculating Acceleration As a roller-coaster car starts down a slope, its speed is 4 As a roller-coaster car starts down a slope, its speed is 4

m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. But 3 seconds later, at the bottom, its speed is 22 m/s. What is its average acceleration?m/s. What is its average acceleration?

Look Back and CheckLook Back and Check

Does your answer make sense?Does your answer make sense?

The answer is reasonable. If the carThe answer is reasonable. If the car’’s speed increases s speed increases by 6 m/s each second, its speed will be 10 m/s after 1 by 6 m/s each second, its speed will be 10 m/s after 1 second, 16 m/s after 2 seconds, and 22 m/s after 3 second, 16 m/s after 2 seconds, and 22 m/s after 3 seconds.seconds.

Calculating AccelerationCalculating AccelerationPractice ProblemPractice Problem

A certain car brakes from 27 m/s to A certain car brakes from 27 m/s to restrest in 9 in 9 seconds. Find the carseconds. Find the car’’s average acceleration.s average acceleration.

(0 m/s – 27 m/s ) ÷ 9 s = (0 m/s – 27 m/s ) ÷ 9 s = --27 m/s ÷ 9 s = 27 m/s ÷ 9 s = -3 -3 m/sm/s22

This is aThis is a negative accelerationnegative acceleration, , which is also which is also calledcalled aa deceleration (slowing down) deceleration (slowing down)

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