8th Grade Forces And Motion Motion - NJCTL

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Slide 1 / 159Slide 2 / 1598th GradeForces2015-10-27www.njctl.orgSlide 3 / 159Slide 4 / 159Forces and MotionClick on the topic to go to that section· Motion· Graphs of MotionMotion· Forces· Newton's Laws of Motion· Newton's 3rd Law & MomentumReturn to Tableof ContentsSlide 5 / 159Slide 6 / 159What does it mean to be in motion?What does it mean to be in motion?With a partner, come upwith a scientificexplanation of what itmeans if an object is inmotion. Don't just say anobject is moving!An object is in motion if itchanges position inrelation to a certain place,called a reference point.Reference points areplaces or objects used todetermine the motion of anobject.It is extremely important to choose reference pointscarefully.

Slide 7 / 159Slide 8 / 159Relative MotionMeasuring MotionMotion is relative asit is dependent uponthe reference point.Are you in motionright now? Thinkabout it.Speed is one of the many ways we measure motion.Speed is a measure of the distance traveled per unit oftime.That means you can find the speed of any object that isin motion!Are you in motion compared to your desk?Are you in motion compared to the sun?Slide 9 / 159Slide 10 / 159Finding SpeedFinding SpeedSpeed Distance TimeDiscussion time!· What are some possible units to measure speed? Rememberthat speed distance/time!· How do you think speed is measured when driving in a car?and· How would you measure speed of an engine? For reference,an animation of an internal combustion engine is shown below.We can rearrange the letters in the speed equation and solvefor any of the other 2 pieces of information.Slide 11 / 159Slide 11 (Answer) / 159Units for SpeedUnits for SpeedThe SI unit for distance is meters (m) and for time is seconds (s).Given these units, what will be the SI unit for speed? (Hint: recallthe speed equationspeed distance/time)Given these units, what will be the SI unit for speed? (Hint: recallthe speed equationspeed distance/time)AnswerThe SI unit for distance is meters (m) and for time is seconds (s).meters/secondwhich is usually shortened tom/s[This object is a pull tab]

Slide 12 / 159A60000 m/sA60000 m/sB0.02 m/sB0.02 m/sC600 m/sC600 m/sD0.002 m/sD0.002 m/sSlide 13 / 1592 A blimp travels at 3 m/s for 1500 s. Whatdistance does the blimp cover in that time?D[This object is a pulltab]Slide 13 (Answer) / 1592 A blimp travels at 3 m/s for 1500 s. Whatdistance does the blimp cover in that time?A500 m/sA500 m/sB4500 m/sB4500 m/sC4500 mC4500 mD500 mD500 mSlide 14 / 159Answer1 A snail travels a distance of 10 m in 6000seconds. What is the snail's average speed?Answer1 A snail travels a distance of 10 m in 6000seconds. What is the snail's average speed?Slide 12 (Answer) / 159C[This object is a pulltab]Slide 15 / 159SpeedWhen we talk about speed, it is important to know that there isa difference between instantaneous speed and average speed.Average speed can be calculated by dividing the total distanceby the total time. This is what is usually calculated by runnersin a race.Instantaneous speed isthe speed of an object atany moment in time (aninstant of time). Can youthink of an examplewhere you would useinstantaneous time?Manipulate the speed of each car, solve for time, and predict whichcar will win!

Slide 16 / 159Average vs Instantaneous SpeedIt might take 3 hours to travel 300 km in a car. What would theaverage speed of the car be? Calculate it now.Does that mean the car was goingthat speed for the whole 3 hoursof the trip?When you go on a trip in the car,do you go the same speed thewhole time? Talk to a partnerabout this.Slide 17 / 159Average vs Instantaneous SpeedHave you ever run a mile? Do you think you ran at the exact samespeed the entire mile?Think aboutwhat runnersdo at thevery end of arace.Slide 18 / 159Average vs Instantaneous SpeedWhen you ride on the busto school, does the busdriver travel at the samespeed the entire trip?Slide 19 / 1593 Your teacher times your mile run at 7.5 minutes,that means your speed was 0.13 mile/min. Was thisyour average speed or your instantaneous speed?AverageA SpeedSchool buses and othervehicles havespeedometers thatmeasure the speed of thevehicle at a specificmoment in time.InstantaneousB SpeedDo speedometers measure average speed or instantaneous speed?Slide 19 (Answer) / 1593 Your teacher times your mile run at 7.5 minutes,that means your speed was 0.13 mile/min. Was thisyour average speed or your instantaneous speed?4 A student has built a model car that is designed torun at a constant speed. What should the studentmeasure to test whether the car runs at a constantspeed, average or instantaneous speed?avg speed AnswerAverageA SpeedSlide 20 / 1591 mile/ 7.5 min Instantaneous0.13 mile/minB Speed[This object is a pulltab]A Average SpeedB Instantaneous Speed

Slide 20 (Answer) / 159A Average SpeedAnswer4 A student has built a model car that is designed torun at a constant speed. What should the studentmeasure to test whether the car runs at a constantspeed, average or instantaneous speed?instantaneousspeedB Instantaneous Speed[This object is a pulltab]Slide 21 / 1595 A swordfish travels for two hours. The firsthour he covers 110 kilometers, and thesecond hour he covers 84 kilometers. Whatis the average speed of the swordfish?A110 km/hB84 km/hC97 km/hD194 km/hHint: Remember thatAverage speed is totaldistance travelled dividedby total timeSlide 21 (Answer) / 1595 A swordfish travels for two hours. The firsthour he covers 110 kilometers, and thesecond hour he covers 84 kilometers. Whatis the average speed of the swordfish?110 km/hB84 km/hC97 km/hD194 km/hCHint: RememberthatAverage speed is totaldistance travelled dividedby total timeAnswerA[This object is a pulltab]Slide 22 (Answer) / 159A30 secondsB2 minutesC188 secondsD90 secondsAnswer6 A dog walks outside to go the bathroom every day.On a given day, she walks 75 meters before she findsa spot to use the bathroom. She walks at an averagespeed of 2.5 meters per second. How long does it takeher to find a place to use the bathroom?ASlide 22 / 1596 A dog walks outside to go the bathroom every day.On a given day, she walks 75 meters before she findsa spot to use the bathroom. She walks at an averagespeed of 2.5 meters per second. How long does it takeher to find a place to use the bathroom?A30 secondsB2 minutesC188 secondsD90 secondsSlide 23 / 159VelocityVelocity is another way to measure motion. Simply put, velocityis the speed of an object with a direction included.Runner's speed: 10 km/hrRunner's velocity: 10 km/hr to the East[This object is a pulltab]What do you notice about the units for speed and velocity?

Slide 24 / 159Slide 25 / 159Why is velocity important?Have you ever been in an airplane? Would would be the consequence ofa pilot only knowing the speed of other nearby planes?Tornadoes travel at about 170 km/h.Why is knowing the velocity of atornado important?7Carlos and Gina are riding on their horses togo into town. They travel 70 meters in 7 secondsgoing west. What is their velocity?A490 m/s westB10 m/s westC490 m/sD10 m/sSlide 25 (Answer) / 159A490 m/s westB10 m/s westC490 m/sD10 m/sAnswerCarlos and Gina are riding on their horses togo into town. They travel 70 meters in 7 secondsgoing west. What is their velocity?B[This object is a pulltab]Slide 26 (Answer) / 1598 A car travels 100 km/h west for 2 hours. The carthen travels 50 km/h east for one hour. What is thecar's final position relative to its starting position?A50 km westB150 km westC250 km westD50 km eastHint: Find the distanceand direction traveled foreach leg of the trip first.Draw these distances ona number line using 0kmas the starting point.Slide 27 / 1598 A car travels 100 km/h west for 2 hours. The carthen travels 50 km/h east for one hour. What is thecar's final position relative to its starting position?A50 km westB150 km westC250 km westD50 km eastHint: Find theBdistanceand direction traveled foreach leg of the trip first.Draw these distances ona number line using 0kmas the starting point.Answer7Slide 26 / 159Graphing Motion[This object is a pulltab]Return to Tableof Contents

Slide 28 / 159Slide 28 (Answer) / 159Graphing MotionGraphs can be used to show motion and can be used to determinerelationships!Graphs can be used to show motion and can be used to determinerelationships!When graphing data, position should be on the y-axis and time on thex-axis. Drag and drop the variables onto the correct axis on the graphbelow.When graphing data, position should be on the y-axis and time on thex-axis. Drag and drop the variables onto the correct axis on the graphbelow.PositionPositionTimeTimeAnswerGraphing MotionPositionTime[This object is a pull tab]Slide 29 / 159Slide 30 / 159Graphing MotionGraphing MotionUse the graph below to calculatespeed at 1, 2, and 3 seconds.Do you notice a pattern?6 m/ 3s 2 m/s2 m/ 1s 2 m/s4 m/ 2s 2 m/sThe speed is 2 m/s at each of the three seconds! In otherwords, the speed is constant.Slide 31 / 159Graphing MotionSlide 31 (Answer) / 159Graphing MotionWhen interpreting a graph, it is important to look for relationshipsbetween variables. These relationships can be strong, weak, or notpresent at all.The graph below shows a strong relationship between position andtime. Can you describe what this relationship is?The graph below shows a strong relationship between position andtime. Can you describe what this relationship is?As the timeincreases at aconstant rate, sodoes the position.AnswerWhen interpreting a graph, it is important to look for relationshipsbetween variables. These relationships can be strong, weak, or notpresent at all.[This object is a pull tab]

Slide 32 / 159Slide 33 / 159Graphing MotionGraphing MotionA weak relationship is when significant changes in one variablecause minimal changes in the other variable. Is there any pattern inthe graph below? Circle the patterns.When there is no relationship between the variables, there will notbe a pattern present. Is there any pattern in the graph below?Slide 34 / 159Slide 35 / 159The Importance of SlopePosition versus time graphs can be used to find speed andcompare speeds.When we talk about the slope of a line, weare talking about how steep a line is.Look at the skier tothe right. He is on avery difficult trail.The Importance of SlopeIn a position versus time graph, the y-axis is the position and thex-axis is the time. Recall that the relationship between positionand time is speed. So when we are looking at the slope, we arelooking at the speed .The slope of theblack line gives usthe speed of thebicycler.Would an easier trailbe steeper or moreflat?How would theslopes of these twotrails compare?The steeper the slope of the line on a position versus time graph,the greater the speed!Slide 36 / 159Slide 36 (Answer) / 1599 Which walker has a greater speed?How can you tell in terms of the slopes of thegraphs?Answer9 Which walker has a greater speed?How can you tell in terms of the slopes of thegraphs?ABAWalker #2 because theslope is steeper. Thiswalker coveredthe same distance inless time than walker[This object is a pull#1. tab]B

Slide 37 / 159Graphing Motion Simulation LabClick on the image to the left to launchthe simulation. You will need todownload it to be able to use it.Click on the CHARTS tab at the top.Minimize the velocity graph and theacceleration graph by clicking on theRED dash on each graph. KEEPPOSITION!CLICK PLAYDrag the man to the RIGHT at aconstant speed, STOP, and finally dragthe man at a constant speed Left back tothe starting point (zero).Slide 38 / 159AccelerationConstant speed is when an object's speed does not change; however,most objects do not travel at a constant speed. Acceleration is a wayto measure changing motion.Do you walk at the exact same speedfrom class to class? What if you are latefor class?Are you ever accelerating when you goto class? Can you define acceleration?Relate the shape of the graph (slopes!) to the man's motion.Slide 39 / 159AccelerationAcceleration occurs when there is a change in velocity. Remember,velocity is speed with direction.So acceleration occurs any time there is an increase in speed, adecrease in speed, or a change in direction.Slide 40 / 159AccelerationAcceleration is a measure of the change in velocity per unit of time.Here is the equation for acceleration.a vf -votacceleration (final velocity-initial velocity)timespeedchange indirectionSlide 41 / 15910 A school bus driver sees an old man crossing thestreet at an intersection. The bus driver hits thebrake pedal and turns the steering wheel to avoidhim. Describe the acceleration of the bus.Slide 41 (Answer) / 15910 A school bus driver sees an old man crossing thestreet at an intersection. The bus driver hits thebrake pedal and turns the steering wheel to avoidhim. Describe the acceleration of the bus.A It increased speedA It increased speedB It decreased speedB It decreased speedC It changed directionC It changed directionAnswerspeedB&C[This object is a pulltab]

Slide 42 / 15911 A dragster launches from rest to 50 mi/hr at thestart of a race. How did the car accelerate?Aincreased speedAincreased speedBdecreased speedBdecreased speedCchanged directionCchanged directionSlide 43 / 159Answer11 A dragster launches from rest to 50 mi/hr at thestart of a race. How did the car accelerate?Slide 42 (Answer) / 159A[This object is a pulltab]Slide 43 (Answer) / 159Practice Solving for AccelerationPractice Solving for AccelerationThe school bus picks you up at the bus stop and takes 60seconds to accelerate to 120 km/h. What is the acceleration ofthe school bus?The school bus picks you up at the bus stop and takes 60seconds to accelerate to 120 km/h. What is the acceleration ofthe school bus?a (120 km/h - 0 km/h)o sa vf -v60tAnswera vf -vota 2 km/h per second[This object is a pulltab]12 A plane's speed increases from 25 m/s to 60 m/s in 5seconds. What is the acceleration of the plane?Slide 44 (Answer) / 15912 A plane's speed increases from 25 m/s to 60 m/s in 5seconds. What is the acceleration of the plane?AnswerSlide 44 / 159a (60 m/s - 25 m/s)5sa 7 m/s/s OR 7m/s2[This object is a pulltab]

Slide 45 / 15913 After traveling for 10 seconds, a runner reaches aspeed of 12m/s. If the runner started from rest, whatis the runner's acceleration?Answer13 After traveling for 10 seconds, a runner reaches aspeed of 12m/s. If the runner started from rest, whatis the runner's acceleration?Slide 45 (Answer) / 159a (12 m/s - 0 m/s)10 sa 1.2m/s2[This object is a pulltab]Slide 46 / 15914 A parachute opens and slows a skydiver from 65m/sto 45m/s in a period of 5 seconds. What is theacceleration of the skydiver?Answer14 A parachute opens and slows a skydiver from 65m/sto 45m/s in a period of 5 seconds. What is theacceleration of the skydiver?Slide 46 (Answer) / 159a (45m/s - 65m/s)5sa -4m/s2 ordecelerated 4m/s2[This object is a pulltab]Slide 47 / 159Slide 47 (Answer) / 159Acceleration and GraphsIf the speed and direction of an object are constant, then theacceleration is zero. Look at the car's speed at 20s, 60s, and 100s.Is the car accelerating?If the speed and direction of an object are constant, then theacceleration is zero. Look at the car's speed at 20s, 60s, and 100s.Is the car accelerating?AnswerAcceleration and GraphsOnly if the car is changingdirections. Based on speed alone,the car does not accelerate.[This object is a pull tab]

Slide 48 / 159Slide 49 / 15915 A driver hits the brakes to slow down at anintersection. As the car's speed is decreasing it has:Acceleration and GraphsA positive accelerationB negative accelerationC no accelerationD more information is neededAcceleration ispositive when speedis increasing.Negative acceleration(deceleration) is whenspeed is decreasing.How could you describe the slopes of each ofthese lines?Slide 49 (Answer) / 159Slide 50 / 159D more information is neededTime (s)[This object is a pull tab]CYBYDSpeed (m/s)CTime (s)xSpeed (m/s)xYCx[This object is a pull tab]We will us a constant velocity vehicle to collect dataand graph our results.The graph will help us determine the average speed.Time (s)xConstant Speed Graphical Analysis LabTime (s)Speed (m/s)Time (s)Time (s)YAnswerSpeed (m/s)YYSlide 51 / 15916 Which of the following graphs shows a positiveacceleration?AxxTime (s)DTime (s)Slide 50 (Answer) / 159xYSpeed (m/s)BSpeed (m/s)AnswerC no accelerationBYSpeed (m/s)AA positive accelerationB negative acceleration16 Which of the following graphs shows a positiveacceleration?Speed (m/s)15 A driver hits the brakes to slow down at anintersection. As the car's speed is decreasing it has:x

Slide 52 / 159Acceleration and GraphsSlide 53 / 159Distance vs. Time Graphs of AcceleratingObjectsThe slope of a position versus time graph can also showacceleration.Click on the image to download thesimulation.Click on the CHARTS tab.Type in 1 m/s2 into the accelerationvalue and hit play.If the slope curves and getssteeper, then positiveacceleration is occurring.If the slope curves and becomesless steep, thennegativeacceleration is occurring.Sketch theshape of thedistance vs.time graph:Slide 54 / 15917 Which of the following speed vs time graphs (on theleft) correspond to the position vs time graph on theright?Slide 54 (Answer) / 15917 Which of the following speed vs time graphs (on theleft) correspond to the position vs time graph on theright?ABBAnswerASketch theshape of thevelocity vs.time graph:A[This object is a pulltab]CCSlide 55 / 159Slide 56 / 159Accelerated Motion on an Inclined Plane LabIn this lab you will record the time it takes for a car togo different distances down an inclined plane.The data will be graphed and then you will analyze theresults.ForcesReturn to Tableof Contents

Slide 57 / 159Slide 58 / 159Forces Affect MotionWhat Are Forces?At your table, make a list of ways forces can affect objects.There are many ways. Write a few of these ways below.Forces are orin a given direction.Forces affect how objects move.Slide 59 / 159Slide 60 / 159The Big Idea.Units of ForceSince forces can cause changes in the speed or direction of anobject, we can say that forces cause changes in velocity, soforces cause acceleration!ForcesForces are measured in newtons (N).You probably measure yourself on a scale in pounds.One pound is equal to 4.448 newtons.Just like velocity, force has direction. When forces aredemonstrated both magnitude and direction should be shown.cause10 NWhat is the magnitude of the force shown above? How about thedirection?AccelerationSlide 61 / 159Slide 62 / 159Unbalanced ForcesBalanced ForcesIf you and a friend both push with the same strength on each side ofa table, will it move?If the effects of the forces don't cancel each other out (one force isstronger than others), the forces are unbalanced forces. Unbalancedforces do cause a change in motion; speed and/or direction.Two or more opposite forces acting on an object are consideredbalanced if their effects cancel each other out. Balanced forces donot cause a change in an object's motion.The box to the right isat rest and will remainat rest since theopposite forces actingon it are balanced.Think about Tug-Of-War.How does one side win?8N8N

Slide 63 / 159Slide 64 / 159Unbalanced ForcesUnbalanced Forces8N15 NTwo ways to interpret this diagram are to say:8N15 Nthere is a 15N force to the right and an 8N force to the leftDoes the box accelerate?Which way do you think the box will move and why?What does the negative on the -8N tell us?Slide 65 / 15918 Forces are all around us. Which of the followingdo you think are examples of forces? (choose allthat apply)Slide 65 (Answer) / 15918 Forces are all around us. Which of the followingdo you think are examples of forces? (choose allthat usclesDWindDWindSlide 66 / 15919 What is the SI unit for force?Answerwe can say there is a 15N force and a -8N force.The box was initially at rest. Since the forces acting on the boxare unbalanced, the box will start moving.A&B[This object is a pulltab]Slide 66 (Answer) / 15919 What is the SI unit for This object is a pulltab]CNewtonsCNewtons

20 A 10 N force acts on a car and at the same time,a -20 N force acts on the car. What is the netforce acting on the car and is it balanced?A -30 N unbalancedB -10 N unbalancedC -10 N balancedHint: Net force is the total(or sum) of all the forcesacting on an object.D 30 balancedSlide 67 (Answer) / 15920 A 10 N force acts on a car and at the same time,a -20 N force acts on the car. What is the netforce acting on the car and is it balanced?A -30 N unbalancedB -10 N unbalancedC -10 N balancedAnswerSlide 67 / 159BHint: Net force is the total(or sum) of all the forcesacting on an object.[This object is a pulltab]D 30 balancedSlide 68 / 159FrictionForces are present all around us, but can not usually be seen.Friction is a force that resists motion and we experience daily.When you run, walk, sit on the couch,brush your hair, and write youexperience friction.You are experiencing friction rightnow!Slide 70 / 159Static FrictionStatic friction acts on objects that are not moving. Have you everwondered why it is so hard to start moving a heavy object like adresser or couch, but then once it starts moving it is easier?Slide 69 / 159FrictionThe force of friction is caused by microscopic particles touching eachother. These microscopic pieces on both surfaces cause friction.Friction is affected by how hard the surfaces push together and thetypes of surfaces involved.There are many types offriction.Click here to see the force of friction clipSlide 71 / 159Sliding FrictionSliding friction occurs when objects slide over each other. Slidingfriction is easier to overcome than static friction. That is why thecouch is easier to move once it starts sliding!Sliding friction is also known as kinetic friction.That is because you have to overcome the force of static friction!Static friction holds the couch in place and keeps it from moving.Click here to see sliding friction in action.

Slide 72 / 159Slide 73 / 159Fluid FrictionRolling FrictionFluid friction occurs when objects move through a fluid.Remember, air is a fluid, so you continuously experience fluid friction!Rolling friction existswhen objects rollacross surfaces.With a partner, make alist of other examplesof rolling friction. Hint:There are manyexamples in sports.Click here to see the effects of fluidfriction.Slide 74 / 159Slide 75 / 159FrictionThe force of friction is measured in Newtons like all other forces.When you are trying to determine where to put the friction force,just remember that friction acts opposite to motion!21 Friction acts more on objects in motion than itdoes on objects at rest.TrueFalseforce applied byperson pushing boxstationary boxstatic frictionforceSlide 75 (Answer) / 15921 Friction acts more on objects in motion than itdoes on objects at rest.True22 Friction always opposes the motion of anobject.TrueAnswerFalseSlide 76 / 159False[This object is a pulltab]False

Slide 76 (Answer) / 15922 Friction always opposes the motion of anobject.TrueAnswerFalseTRUESlide 77 / 159GravityForces are present all around us and always act in pairs, so we usuallyexperience more than one force. Gravity is a force that pulls objectstowards each other.How does gravity act on objectshere on Earth? Use the picture tothe right to help you with youranswer.[This object is a pulltab]Slide 78 / 159Slide 79 / 159Factors Affecting GravityLaw of GravitationThe Law of Universal Gravitation tells us that gravity acts betweenall objects in the universe. This means that without exception, anytwo objects in the universe attract each other!Gravity is affected by both mass and distance. The greater the distancebetween two objects, the less the gravitational force between them. Thegreater the mass of the object, the greater the object's gravitationalforce.You have learned about mass in the past. Can you define mass?Which of theseexamples hasmore gravity?Why?Slide 80 / 15923 The force of gravitation between an objectand a planet is increased as they moveaway from each other.TrueTrueFalseFalseAnswer23 The force of gravitation between an objectand a planet is increased as they moveaway from each other.Slide 80 (Answer) / 159False[This object is a pulltab]

Slide 81 / 15924 The force of gravitation between an objectand a planet is decreased if the objectincreases mass.TrueTrueFalseFalseAnswer24 The force of gravitation between an objectand a planet is decreased if the objectincreases mass.Slide 81 (Answer) / 159False[This object is a pulltab]Slide 82 / 159Slide 83 / 159Wait, so mass affectsgravity?Mass and WeightWhat is weight?You have also learned the difference between mass and weight in thepast. What can you recall about mass and weight?Weight is a measure of the gravitational force exerted on an object.Weight varies depending on gravitational force, but mass does not.Weight mass x gravityThink aboutastronauts on theInternationalSpace Station.What do youknow about theirmasses andweights?Our moon has a gravity that isone sixth of that on Earth.What would that do to yourweight on the moon?Would your mass change onthe moon?Slide 84 / 159What is "g"?"g" is the acceleration due to gravity.On Earth, our "g" is approximately 9.8 m/s2 .On other planets, acceleration due to gravity will vary dependingon the mass of the planet. In general, the more massive theobject, the larger the value of g!Jupiterg 26.1 m/s2Earth's Moong 1.67 m/s2Slide 85 / 15925 A 50 kg kid is on planet Earth, where g 9.8 m/s2.What is the boy's weight?A5.1 m/sB490 NC490 kgD5.1 N

Slide 85 (Answer) / 15925 A 50 kg kid is on planet Earth, where g 9.8 m/s2.What is the boy's weight?Slide 86 / 15926 A 50 kg kid is on planet Earth, where g 9.8 m/s2.What is the boy's mass?5.1 m/sA50 kgB490 NB490 NC490 kgC490 kgD5.1 ND5.1 NAnswerAB[This object is a pulltab]Slide 86 (Answer) / 15926 A 50 kg kid is on planet Earth, where g 9.8 m/s2.What is the boy's mass?Slide 87 / 15927 A 50 kg kid is on the moon, where g 1.67 m/s2.What is the boy's weight?50 kgA83.5 kgB490 NB29.9 kgC490 kgC83.5 ND5.1 ND29.9 NAnswerAA[This object is a pulltab]Slide 87 (Answer) / 15927 A 50 kg kid is on the moon, where g 1.67 m/s2.What is the boy's weight?Slide 88 / 15928 A 50 kg kid is on the moon, where g 1.67 m/s2.What is the boy's mass?83.5 kgA83.5 kgB29.9 kgB50 kgC83.5 NC83.5 ND29.9 ND50 NAnswerAC[This object is a pulltab]

Slide 88 (Answer) / 159Slide 89 / 15928 A 50 kg kid is on the moon, where g 1.67 m/s2.What is the boy's mass?B50 kgC83.5 ND50 NBAnswerA83.5 kg29The larger the planet, the larger the .AmassBweightC gravityDall could be correct[This object is a pulltab]Slide 89 (Answer) / 159Gravity and MotionThe larger the planet, the larger the .AmassBweightGalileo showed that falling objects accelerate equally no matterwhat their mass is. This is strictly true when gravity is the onlyforce acting on a falling object and is known as free fall.When an object is in free fall, it accelerates at 9.8 m/s2Answer29Slide 90 / 159C gravityDall could be correctD[This object is a pulltab]If these two stones are droppedfrom the same height at the sametime, which hits the ground first?10kgClick here to see a bowlingball and golf ball beingdropped1kgSlide 90 (Answer) / 159Slide 91 / 159Gravity and MotionGravity and MotionGalileo showed that falling objects accelerate equally no matterwhat their mass is. This is strictly true when gravity is the onlyforce acting on a falling object and is known as free fall.When an object is in free fall, it accelerates at 9.8 m/sIf these falling rocks onlyhad gravity acting on them(in free fall), they wouldIf these two stones are droppedboth fall at the same rate offrom the same height at the same9.8 m/s2 . They would bothtime, which hits the ground first?hit the ground at the sametime!10kgAnswer2[This object is a pull tab]Click here to see a bowlingball and golf ball beingdropped1kgThe following video shows a feather and a ball bearing beingdropped from a small height.Click here to see a feather and a ball bearingbeing dropped.Which simulation showed the objects in free fall?Critical thinking: What was happening in the simulation that did notillustrate free fall?

Slide 91 (Answer) / 159Slide 92 / 159Gravity and MotionAnswerThe following video showsfeatherand a ballIn theafirstsimulation,the bearingobjects beingdropped from a small fellheight.at different rates. In the secondsimulation, the objects fell at thesame rate. The second simulationillustrates free fall.Click here to see a feather and a ball bearingbeing dropped.Critical thinking: Move on to thenext slide to learn the answer tothis question!Air ResistanceObjects are not always truly in free fall because theyexperience air resistance. Air resistance is a fluid frictionexperienced by falling objects. When objects experience airresistance, they don't fall at a rate of 9.8 m/s2.Try this: Crumple up two pieces of paper individually and dropthem both from the same height at the same time. Which hitsthe ground first? Now drop a crumpled piece of a paper and anon-crumpled piece of paper in the same way. What's thedifference?[This object is a pull tab]Which simulation showed the objects in free fall?Click here to see a featherand a hammer being droppedon the moon. What happenswith no air resistance?Critical thinking: What was happening in the simulation that did notillustrate free fall?Slide 93 / 159Slide 94 / 159Net ForceAir ResistanceThe flat piece of paper fell at a slower rate because it had moresurface area. This greater surface area resulted in the paperexperiencing air resistance. For the crumpled paper, airresistance was probably very tiny and thus could be ignored.The crumpled paper was essentially in free fall.As you know, many forces are acting on us and other objects.To determine the total force acting on an object, the

8th Grade Forces 2015-10-27 www.njctl.org Slide 3 / 159 Forces and Motion · Motion Click on the topic to go to that section · Graphs of Motion · Newton's Laws of Motion · Newton's 3rd Law & Momentum · Forces Slide 4 / 159 Motion Return to Table of Contents Slide 5 / 159 What does it mean to be in

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Grade 6 Science, Unit 4 Forces and Motion Overview Unit abstract Forces and Motion focuses on helping students understand ideas related to why some objects will keep moving and why objects fall to the ground. Students will be able to apply Newton’s third law of motion to related forces to explain the motion of objects.

Chapter: Motion, Acceleration, and Forces Table of Contents Section 3: Motion and Forces . also are accelerated. Acceleration This acceleration makes them feel as if a . Sometimes it is obvious that a force has been applied. 3 Motion and Forces But other forces arenÕt as noticeable. Changing Motion

Grade 4 NJSLA-ELA were used to create the Grade 5 ELA Start Strong Assessment. Table 1 illustrates these alignments. Table 1: Grade and Content Alignment . Content Area Grade/Course in School Year 2021 – 2022 Content of the Assessment ELA Grade 4 Grade 5 Grade 6 Grade 7 Grade 8 Grade 9 Grade 10 Grade 3 Grade 4 Grade 5 Grade 6 Grade 7 Grade 8

The ISO 14001 Standard has been through a number of revisions since it was first published in 1996. ISO Standards are reviewed every five years to establish if a revision is required in order to keep them current and relevant. The current Standard, ISO 14001:2015, responds to the increasing need for management systems to be integrated by using “Annex SL”, a common format for management ISO .