2Chapter 13 – A Need For Safety In this chapter you will learn about:Common driver errorsTransportation data and studies that help make our roads safeWork through scenarios to answer questions like:What factors lead to traffic accidents?What is the connection between reaction time and vehicle collisions?What are the most common injuries?How are vehicles and roads designed to keep us safe?
313.1 – Analyzing the ErrorInjuries from vehicle collisions range from scratches and bruises to serious internal injury causing deathHow safe are you?50 times more likely to die in a road collision than in an _____________________5 times more likely to be killed in a road collision than to be ______________Many times more likely to be injured in a vehicle collision
4InjuriesEach year, more than __________Canadians are injured in motor vehicle collisionsInjures include:Cuts, bruises, broken bones_________________________ and _________ injuriesLeading to blindness, paralysis, brain damage
5Did you Know?More accidents happen on __________ than on any other day of the week…Why?
613.2 – Reaction TimeThe time it takes you to recognize a problem and act on it is called ___________ _______Even if you are alert and react very quickly, there are many factors that affect a driver’s ability to stop____________________________________Brake failure… Fail.
7Some drivers have a habit of ______________ _________________ These drivers do not have enough _________ _______ if the car in front stops suddenly.What are the potential hazards in the image?
8Reaction Time and Distractions A distraction is anything that takes your attentions away from what you are ___________________________Common distractions outside the vehicle:Common distractions inside the vehicle:Distractions you have control over:
9Fatigue and Reaction Time Sleepy drivers are a serious danger:_______________________________________________ into a ditch________________________ into on-coming traffic
10Some people try to stay awake by drinking coffee and energy drinks that contain caffeine - _________________Stimulants ___________________ and _____________ reaction time
11Effects of the stimulant ______________ and the driver is ____________ than before – and therefore has a ____________________________________ of caffeine, loud music, cold air, or pinching yourself will keep awake____________ o a safe parking place and ___________________
12Reaction Time and Drugs Anything that prevents you from functioning normally means that you are ______________________, _________________, _____-_______________ drugs can make it dangerous for a user to drive
13Alcohol and DrivingAlcohol is a ________________:_______ reaction time_________ co-ordinationMakes the drinker __________Alcohol is absorbed from the __________ directly into the _____________Body recognizes the alcohol as a _______Liver can convert _____________into less harmful substances, but is soon ________________
14Blood Alcohol Concentration It is difficult for a person to know if they have consumed too much alcohol and should not drive.Law enforcement use a BAC – ____________ _________________________If a person’s BAC is 0.08, they have _______ of alcohol for each mL of bloodBAC is measured in __________________in a ____________________
15Blood Alcohol and the Law In Canada, ______________ is generally considered the _______________A police officer can charge drivers who have ______________ on their breath when they are pulled over – the charge is ____________________Drivers are considered to be impaired when their _____________________ than normal:__________________________________________________________________________
16Other factors that can affect ability to drive: __________any one person can drink before exceeding the legal limit of 0.08 mg/mL ______________:_________________ consumed___________________________Other factors that can affect ability to drive:Amount of ________ consumedAbout of _________ person has had
1713.3 – Collision InjuriesIndividuals involved in vehicle collisions may sustain _________ and ______________ injuriesPhysical and emotional stress is referred to as ___________Physical trauma: cuts, scrapes, broken bones, whiplash, metal injuryEmotional trauma: grief, regret, fear of driving
18Physical Trauma Some injuries can be healed __________ ________ ________________ or ____________________ required to correct some damageSome injuries cannot be healed:Major ____________________________________________ injuries
19Mental Trauma Emotional trauma is not “_________” Emotional ____________ can assist individuals
20WhiplashWhiplash occurs when the ______________ ___________ of the neck are ____________Common injury for the people in the _______ ___ of a _________________
21Properly ___________________ prevent the head from flying backward beyond the back of the seat Chiropractic or massage therapy can be helpful in treating whiplash
22Grief How would you feel? Talking to a professional who understands sadness helps many people deal with emotional pain
2313.4 – Protection and Prevention ______________are built into ________ and _____ to protect you in case of a road accident_____ concerning proper driving procedures_________________________designed to make us aware of specific traffic dangers
24Safe VehiclesIn Alberta, the law says that every person must ______________________; small children and babies are restrained using specially designed seatsDoes this law keep you safe?What has happened to the number of fatalities since the seal belt laws were passed in 1987?
26Other Safety FeaturesSeatbelts work ______________ to restrain passengers.Other safety features are designed to work only when ________________________:Air bagsAnti-lock braking systemsCrumple zonesSide impact beams
27Air bags _________ when a collision occurs _________ drivers and passengers against impact
28Anti-lock Braking Systems Provide better _______________ in slippery conditions
29Crumple Zones Located on the outer parts of the car near the bumpers _____________________ of the collision so the passengers feel less effect
30Side Impact Beams Steel beams in the doors Prevent the doors from _____________Protect the people inside the vehicle
31Vehicle MaintenanceMaintenance or continual care is important for all safety features on your vehicle:________ – poor tread causes vehicles to skid easily, affect time for vehicle to slow down__________ – steering mechanism should be checked to make sure vehicle steers when you need it to______________________ – poor condition of wipers makes it hard to see the road ahead
32Safe Roads Roads are designed to be as safe as possible: _____________ – remind people to slow down before intersections or school zones______________ - protect cars from falling over steep edges______________________________ – warn of pedestrian crossing or intersections___________________________ – fall apart on impact to reduce force of a collision
34Chapter 13 SummaryMost collisions are preventable and due to driver errorThe use of alcohol and medications, distractions, and fatigue are often factors in vehicle collisionsThere are many types of injuries caused by vehicle collisionsAccident victims use different methods to healThere are many regulations and road safety features that protect drivers and passengers
36What you will learn about… What is velocity?How to create and interpret a distance/time graphTo calculate the velocity of an object using the formulaWhat effect does increasing velocity have on stopping distance and following distance
3714.1 – Defining Velocity By foot? Bike? Car? How do you know how fast you are going?By foot?Bike?Car?
38Setting a Limit Why are speed limits set? Why do school and playground zones have a limit of 30 km/hr?
39What is Velocity? Distance is a change _____________ Car speedometers use __________ and _____ to determine the speed or velocity of an objectDistance is a change _____________Change in position occurs over a period of _____Velocity is the ___________________ by an object during a ___________________________
40Vehicles travelling at 100 km/h cover a distance of ____km in _____ hour Vehicles travelling 50 km/h cover half that distanceAll descriptions of velocity include _______ (i.e. km/h or m/s)
41d = _______ in ___________ (km) or ________ (m) You can calculate the velocity or any object if you know its change in __________, and the period of _______ over which the change occurred.This is the formula that is used:ord = _______ in ___________ (km) or ________ (m)t = ______ in _______ (h) or ____________ (s)v = __________ in ______ or _____
42Try this:A cue ball travels two meters toward the 8-ball. It takes one second for the cue ball to reach the 8-ball, how fast is the cue ball moving?
43A snowboarder makes it down a 1000 m run in 60 seconds A snowboarder makes it down a 1000 m run in 60 seconds. What is the snowboarder’s velocity?
44Graphing VelocityIt is difficult to make sense of a table full of numbers that show distance and timeDistance (m)Time (s)214638105
45Distance versus Time Graphs Called _________________ graphs for shortIn distance/time graphs:______ describes the object being studied and what variables are being studied______ is plotted on ______ (horizontal)__________ is plotted on the _______ (vertical)The line of “_______” joins the data points and gives us information about the __________
47Constant Velocity, Changing Velocity The ______ of the line represents the ________ of the objectA _______ line shows a _________ velocityA ____________________ line shows a velocity that ___________ over time
48The data below was collected by timing a running student for 10 seconds. Create a labeled graph from the data.Time (s)Distance (m)152103154202563073584094550
49Calculating velocity from a d/t graph You can use a distance/time graph to determine the _________ of an objectDescribe the motion of both of these objectsObject A:Object B:
50The ____ on a distance/time graph shows the ________________ between ____ points The ____ shows the _______________ between ____________ two points
51Calculating velocity from slope The “______________” of a line is referred to as its slopeYou can use the slope of a line to calculate exactly __________ an object is moving___________ = ___________or
52Determine the _____, the __________ interval between the 2 points To find the slope:Choose _____________along the slope; identify the _________________; (x,y)Determine the _____, the __________ interval between the 2 pointsDetermine the ____, the _______ interval between the 2 points____________ the rise and run values into the __________:
53What is the slope of the distance/time graph for Granny’s car?
5414.3 – Calculating Distance If you know the _________ of an object and the _______________it was travelling for, you can determine ________ it travelledor
55Sample problem: You ride your stationary bike for 30 mins ( Sample problem: You ride your stationary bike for 30 mins (.5 hours) and pedal 15 km/h. What is the odometer reading?
56Sample problem: Fearing that her students would be lost without her, Miss Acorn braves a treacherous winter snowstorm to get to school. Miss Acorn travels with an average velocity of 18 km/h and it takes her 90 minutes to get to school. What is the distance between Miss Acorn’s house and the school?
5714.4 – Distance travelled during Reaction Time Why are speed limits different for different roads?When driving, reaction time is the time it takes between the driver recognizing the _______________and ______________________The distance travelled by a vehicle during a driver’s reaction time ______________ as the velocity of the vehicle increases.
58If you have a reaction time of 0 If you have a reaction time of 0.25 seconds, calculate how many meters your vehicle would travel during reaction time if:You are driving 50 km/hYou are driving 110 km/h
59Reaction time and stopping distance The distance that a vehicle travels after the driver applies the brakes is called the __________________The distance travelled during ______________ plus the ________________ is called _________ __________
61Yellow traffic lights are set to last different lengths of time depending on the speed limit of the road.Why is this important?
62Following DistanceCars that follow too closely are at a _______ of having a collision.No matter how _____ your ______________, a vehicle takes a certain distance to stop.The faster a vehicle is moving, the ________ it will take to stop.
63For safety, you should keep a ____________ following distance behind the vehicle in front of you. _____________ is illegal, police can give you a ticket for following too closely!
65What you will learn:Why collisions with small objects cause less damage than collisions with large objectsWhy is takes larger objects a longer time to stop than smaller objectsWhy collisions are less severe at slower velocitiesWhy braking over a longer distance is easier than braking sharplyWhat happens to objects after they collide
6615.1 – Momentum and Mass Momentum is: the measure of an ___________________________________ it is that the object will remain in motion
67The size of the force required to move an object depends on: Force is:A __________________on an objectThe size of the force required to move an object depends on:_____________ the force is applied_____________ of the object_____________ you want the object to go
68General laws related to force Objects not moving will not move until they are __________________Objects moving will ____________________until enough force is added in an _____________ ______________ to stop themObjects with a lot of _______________ will take ____________and ____________ to stop
69Calculating Momentum Momentum = mass x velocity Momentum is calculated by ___________ the ______ of an object times the ___________ it is travelling___________ and __________ objects have more momentumThe formula for momentum is:Momentum = mass x velocityMass in ______________ (kg)Velocity in _____________________(m/s)Momentum in kg•m/s
70A 3 ton (3000 kg) African elephant runs with a velocity of 3 m/s A 3 ton (3000 kg) African elephant runs with a velocity of 3 m/s. An African Rhino weighing 2.00 tons (2000 kg) runs with a speed of 4.5 m/s. Which animal has more momentum?
72A 60 kg girl jogs at a pace of 4 m/s. What is her momentum?
73If a penny weighing 3. 10 grams (0 If a penny weighing 3.10 grams ( kg) reaches a terminal velocity of 105 km/h (29 m/s) when dropped off the Empire State Building. What is the penny’s momentum?Would a penny dropped from the Empire State Building kill a pedestrian below?
74Slowing MomentumBrakes apply a force that stops vehicles by _____________ their momentumBrakes work by using __________:Force that two objects exert on each other when they press against each other
75During braking friction decreases the vehicles momentum. Braking uses friction in two ways:Applying brake petal presses the _____________ against the __________Friction between the _______________ and the surface of the ________.
7615.2 – Changing Momentum is Related to Force _______________when approaching an intersection decreases your velocity slowly; body moves forward __________When velocity decreases slowly so does ______________ (mass x velocity = momentum)Forces, like __________, can be large or small; you can brake ________________
77Impulse Forces can either act for a ______ time or a ______ time. If you brake gradually for a long time (______ force x ______ time)If you brake hard, the car stops quickly and you would feel a ____________(large force x short time)The result is the same either way, the car goes from a _________________(and momentum) to ______________(and zero momentum)
78Impulses __________ momentum (increase or decrease) Impulse is the combination of the ___________ _____ and the _____ during which the force actsImpulses __________ momentum (increase or decrease)The _________ the impulse, the _________ the change in momentumImpulse = force x timeImpulse is measured in __________Force is measured in __________ or Newtons (N)Time is measured in ____________ (s)
79A football player collides with another player A football player collides with another player. The force of the collision is 1000 kg•m/s2. The collision lasts 1 second. What is the impulse?What would the impulse be if the same force of tackle was experienced over two seconds?
80How is impulse effected when a force is applied over a longer period of time? How else can impulse be increased?
81A force of 500 N over 2 seconds will have a ________________ than a force of 50 N over 2 seconds __________ changes, _______ stays the sameA force of 50 N for 5 seconds will have a ______________ than a force of 50 N for 2 seconds_________ changes, _______ stays the same
82You can change momentum by: Applying a _________ forceApplying a force for a longer __________________Which method of changing momentum would you use if you wanted to avoid a collision?
8315.3 – Changing Momentum Quickly Drivers frequently drive 100 km/h (28 m/s) and stop safelyIf your vehicle was travelling 100 km/h and came to a stop in less than one second, the force would be ______________In a car crash a fast moving vehicle comes to a _______________:Metal crumplesGlass shattersBones splinter
84How is the force of a collision related to the time it takes for a change in momentum? Scenario A Scenario B
8515.4 – Is Momentum Lost?When an object _____________, momentum __________ to be lost. Where does it go?The energy from the collision is changed into other forms of _________:_________ in the brakes and between the tires and the road is converted to ______________Energy is lost in the __________ of metal and ___________ of glass
86Conservation of Momentum Two vehicles are travelling along a road in the _________________, each vehicle has its own momentum.What happens to the momentum of the vehicle in the front if it gets hit by the vehicle behind?
87During a collision, one vehicle will gain momentum at the _______________the other vehicle is losing it.______________________________________states that the _____________________of two colliding objects ___________________after their collision.
88Head-on Collisions The motion is in the ____________________ Two vehicles are travelling along a highway in opposite directions and have the same momentum. They hit head on. What happens?The motion is in the ____________________The forces would _______ each other outTheir total ____________________would be _____, so velocity would be _____They would ________________(with a lot of crumpling and injury to those inside
89momentum1 + momentum2 = final momentum Calculate the final momentum of the two vehicles.momentum1 + momentum2 = final momentum
90momentum1 + momentum2 = final momentum What would happen if one vehicle had a greater momentum than the other? Which direction would the two vehicle move in after the collision?momentum1 + momentum2 = final momentum
92What you will learnHow safety features use the laws of physics to protect you from harm during collisionsAbout advances in seat belt and air bag designAbout new advances in technology that could lead to even safer vehicles in the futureHow child safety seats are designed to protect differently than adult seats
9316.1 – How Safety Features Work Remember that when two objects collide that the ____________ of the faster vehicle is ______________ to the slower vehicle.The occupants of the vehicles experience various _________ as their velocities change
94Safety feature serve to slow down the collision: Remember that if the change in momentum (_______) occurs over a _______ period of time, the force will not be as severeSafety feature serve to slow down the collision:Change in momentum occurs over a _________ __________________Occupants feel ______________Occupants receive _________________
95Engineers use ________________________ to determine what will happen to people during a collision
96Crash test dummies are used to help engineers determine how well the ________ _______ in vehicles workCrumple zones:made of crushable ___________ or __________Usually include ______________________________________ when the vehicle is hit
97Remember that impulse = force x time Why use crumple zones?__________________ the collision felt by the occupants of the vehicleIncrease the amount of ____ over which the collision occursRemember that impulse = force x timeIncreasing the time means that a _________ _______ is experienced by the vehicle occupantsThis reduces the __________ experienced by the occupants of the vehicleSmart Car crash testCrash test 1959 Bel Air vs Chevy Malibu
99Restraining features: ________ occupants in one place__________ occupants from hitting dash, windshield, sides or roof of carPrevent someone from being __________ from a vehicleExamples:____________
100Operational features: Operate _______________to keep you safe while drivingExamples:_______________ allow driver to see clearly and warn other drivers of vehicle’s approachRear and side-view _________ assist driver in seeing all parts of the roadTail and _______________ warn other drivers of changes in speed and direction__________ all the vehicle to slow safely
101Structural features (_____ and _________ zones) Rigid features are built from materials that will ____________ or break under extreme pressureDesigned to protect people _______ of the vehicleExamples: heavy frame, roll cage, side impact beams
102Road Safety FeaturesMany roads have road safety features that reduce the ________ of a collision by slowing the ___________Examples:________________________________________________
103Crash cushion: Barrels filled with ________ or _________ _________ or ________ upon impactApply a slowing force to the vehicleLess damaging than a solid barrier
104Guardrails:_____ to lower the momentum of a vehicle and _________ force of the collisionPrevent vehicles from _____________Prevent vehicles from __________________ into traffic
105Break-away light poles: Designed with shear pins that ___________ under the force of collisionVehicle hits post and is _______________ immediatelyForce of impact is ___________
10616.2 – Seat BeltsModern seat belts are designed to prevent your body from moving forward in a collisionOriginal designs were 2-point lap beltsDid not prevent the _____________ from moving forwardModern design is a 3-point shoulder harnessRestrains ________________
107How Seatbelts Work2 Main components:____________________________
108Webbing Made from webbed polyester ____________ 10-15% of its normal lengthHow is this helpful?
109Retractor Unit uses __________ and ________ technology Ratchet: Maintains ____________ in the webbingBelt fits ___________ to your bodyPendulum:___________ stop of vehicle causes pendulum to swing forwardBar _________________and _________ more webbing from coming outTAC seatbelt campaign – KatieTAC seatbelt campaign – Head trauma
112Child RestraintsChildren have ________ bones and muscles along with their comparatively _________ ________Devices are designed to provide the ______ ____________ that this type of body needsTypes of child seats differ based on the ______ of the childThe ______ seat of the car is recommended because there is no dashboard to hit and no chance of injury by an airbag
113Rear facing: Forward facing: Booster seat: Seatbelt: _____________ upright for children who can not yet do soForward facing:_______________ made for child’s narrow shouldersBooster seat:Allows regular seatbelt to ________________Seatbelt:Used by children who can comfortably fit seatbelt
115How Air Bags WorkWorks similarly to a _______________; lower velocity and momentum of vehicle occupantsA ___________________ inside the air bag causes it to inflate in milliseconds__________ cause sodium azide (NaN3(s)) to decompose; ________________of nitrogen gas _________ the airbag
116Evolution of the Air Bag 1st generation: caused many problems2nd generation: deployed at a safer _______ and at a safer ________ (20-35% less than 1st generation)3rd generation: seat sensors detect the ______ of the occupants and ________ the force of the air bag accordinglyModern vehicles feature switches that can turn the passenger air bag off when a _____ is in the _____________