Chapter 1: MotionChapter 1: Motion Section 1:Section 1: Describing and Measuring Describing and Measuring

MotionMotionHow do you recognize motion?How do you recognize motion?

Chapter 1: MotionChapter 1: MotionSection 1: Describing and Measuring Section 1: Describing and Measuring

MotionMotionHow 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

Chapter 1: MotionChapter 1: MotionSection 1: Describing and Measuring Section 1: Describing and Measuring

MotionMotionHow do you recognize motion?How do you recognize motion?

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

Frame of referenceFrame of reference

What is a reference point?What is a reference point?Frame of ReferenceFrame of Reference

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

What is the basic unit of What is the basic unit of length?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 – one hundredth of a 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 1 kilometerin 1 kilometer

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

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

of 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 constantconstant 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

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

directiondirectionWhen you know the When you know the

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

Example: 15 km/hour Example: 15 km/hour westwardwestward

How do you graph motion?How do you graph 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 on the y-axisthe 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

Section 2:Section 2: Slow motion on Slow motion on Planet EarthPlanet Earth

According to their According to their explanation, explanation, known as the known as the theory of theory of plateplate tectonicstectonics, Earth’s , Earth’s plates move ever plates move ever so so slowlyslowly in in various directionsvarious directions

How fast do plates move?How fast do plates move?

Some small plates Some small plates can move as can move as much as several much as several centimeterscentimeters per per year, whereas year, whereas other move only a other move only a few few millimetersmillimeters per yearper year

How can you calculate the How can you calculate the distance an object has moved?distance an object has moved?

Rearrange the Rearrange the speedspeed formula formulaDistance = Distance = SpeedSpeed x x TimeTime

Converting units – choose a Converting units – choose a conversionconversion factor that will allow factor that will allow you to cancel you to cancel unitsunits

D

S T

Section 3: AccelerationSection 3: AccelerationWhat is Acceleration?What is Acceleration?

The The raterate at which at which velocityvelocity changes changes

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

AccelerationAccelerationWhenever an objects speed Whenever an objects speed

increases,increases, the object the object accelerates.accelerates.Pitcher throwing a softballPitcher throwing a softballCar moving from a stopped Car moving from a stopped positionposition

AccelerationAccelerationWhenever an objects speed Whenever an objects speed

SLOWS DOWN, the object SLOWS DOWN, the object deceleratesdecelerates or has negative or has negative acceleration.acceleration.Softball landing in the Softball landing in the catcher’s glove.catcher’s glove.

Car stopping at a red light.Car stopping at a red light.

AccelerationAcceleration

Acceleration can be a Acceleration can be a change in change in directiondirection as well as a change in as well as a change in speed.speed.Runners accelerate as the round a Runners accelerate as the round a

curvecurvecar accelerates as it follows a car accelerates as it follows a

curve in the roadcurve in the roada softball accelerates as it is hit by a softball accelerates as it is hit by

a bat.a bat.

AccelerationAcceleration

Many objects continuously change Many objects continuously change direction without changing speed.direction without changing speed.

Circular motionCircular motion – a motion – a motion along a circular path.along a circular path.

Ex. Seats on a Ferris wheelEx. Seats on a Ferris wheel

Stop and Think Stop and Think

How can a car be accelerating if its How can a car be accelerating if its speed is constant at 65 km/hr?speed is constant at 65 km/hr?

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 – Initial Final velocity – Initial velocityvelocity

TimeTime

How do you interpret graphs to How do you interpret graphs to determine acceleration?determine acceleration?

The acceleration at any moment is The acceleration at any moment is equalequal to the slope of the to the slope of the velocityvelocity time graph at that moment in timetime graph at that moment in time

Acceleration vs. Constant speed