Unit 5: Natural Laws and Car Control in Adverse Conditions NV Driver Education Curriculum Unit 5: Natural Laws and Car Control in Adverse Conditions Presentation 1 of 6 TOPICS: Inertia Momentum Gravity

What are Natural Laws? Natural laws are forces in nature that are always at work. Those that affect you as a driver are: Inertia Gravity Friction Momentum Kinetic Energy Image from: http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr/explaining_motion/forcesandmotionrev1.shtml Retrieved: 09/30/10 In an emergency, these natural laws can work for or against you.

Inertia Objects at rest do not move unless an outside force acts on them. Parked cars stay parked. An object in motion continues to move straight ahead until acted upon by some outside force. Parked image from: http://commons.wikimedia.org/wiki/File:Main_street_hudson_oh.jpg Moving image from:http://www.bmw.com/com/en/newvehicles/7series/sedan/2008/allfacts/engine/driving_dynamics_ddc.html Retrieved: 09/30/10 Moving cars continue to move without acceleration.

Feeling Inertia You experience inertia when you accelerate, decelerate, or drive around a sharp curve. Images From: Driver Right textbook 11th Edition Retrieved: 09/30/10 Acceleration Deceleration In a Curve .

Five Factors that Effect Inertia Sharpness of a turn or curve Speed of vehicle Size, height, weight and load of vehicle Roadway slope Roadway surface condition Black/White image from: http://www.hargreavestraining.com/hargreaves_courses/Driver_CPC_Periodic_Training/Module_2__Vehicle_Load_Handling__Loading Motorcycle image from: http://www.greenlaunches.com/2008/06/index.php?page=3 Sign image from: http://static.howstuffworks.com/gif/shifting-while-towing-1.jpg Dumped load image from: http://articles.sfgate.com/2007-05-10/bay-area/17243099_1_golden-gate-park-big-rig-fulton-street Truck on wet road image from: http://www.pbase.com/pnd1/composition&page=5 Retrieved: 10/06/10

Momentum Momentum is inertia in motion. The momentum of a moving object depends on its mass (weight) and velocity (speed). A large dump truck traveling at 50 mph has more momentum than a small passenger car or motorcycle traveling at the same speed. Freeway image from: http://www.seniordrivers.org/driving/driving.cfm?button=basicskills&sub=merge Motorcyclist image from: http://www.celebridoodle.com/celebridoodle/2010/03/tom-cruise-injured-in-motorcycle-accident.html Retrieved: 10/06/10

Understanding Crashes The greater the momentum, the greater the damage in a collision. As your speed increases, so does the vehicle’s momentum and the likelihood of damage in case of a collision. Rig crash image from: http://toronto.ctv.ca/servlet/an/local/CTVNews/20100309/fatal_crash_100309?hub=TorontoNewHome Red car image from: http://www.carzi.com/2009/03/12/tapout-charles-mask-lewis-ferrari-crash-pictures/ Retrieved:10/06/10 Speeding vehicles cause extensive damage. Heavier vehicles cause more damage.

Essentially, people get injured due to excessive acceleration. Physics of Crashes Essentially, people get injured due to excessive acceleration. Even though the two vehicles have the same speed and the same final speed, the smaller car changes speed AND direction, thus having a much greater acceleration. In order to decrease the acceleration of the car (and the people inside) one must increase the distance (and thus time) over which the collision takes place. Images from: http://scienceblogs.com/dotphysics/2009/02/lighter-but-strong-cars-still-dangerous.php Retrieved: 10/06/10

Crash Test Videos Click on web address to access video clips Insurance Institute for Highway Safety (IIHS) Crash with and without Seatbelt and Airbag http://www.iihs.org/video.aspx/info/airbag_with_without (0:17) real player Insurance Institute for Highway Safety (IIHS) Safety Consequences Size and Weight http://www.iihs.org/video.aspx/releases/pr041409 (2:33) real player Always preview video before showing to students Check content Check availability How Stuff Works image from: http://videos.howstuffworks.com/ IIHS image from: http://www.iihs.org/ Retrieved: 01/21/10 YouTube image from: http://www.youtube.com/ Click on web address to access video clips *Suggest full screen viewing

Kinetic energy is the energy of motion, not the motion itself. The more kinetic energy a vehicle has, the more time and distance it will take to stop. Car photo from: http://green.autoblog.com/2010/07/21/video-testing-the-chevrolet-volt-braking-system/ Braking image from: http://www.discounttire.com/dtcs/safetyBelow45.do Retrieved: 10/06/10

Effect of Speed and Weight A vehicle’s energy of motion changes in proportion to the SQUARE (x2) of the change in speed. Double (2x) your speed and your vehicle will: have four times (22) as much energy of motion need four times (22) as much distance to stop Image from: drive Right textbook 11th Edition Retrieved: 09/30/10

Gravity Gravity is a force that pulls objects towards the center of the earth. On hills gravity makes a vehicle: - slow down when going up hill - speed up when going down hill Sign image from: http://www.cksinfo.com/traffic/roadsigns/warnings/index.html Images from: http://www.aaroads.com/california/i-015ng_ca.html Retrieved: 10/06/10

Center of Gravity The center of gravity is a point in the center of the vehicle where the weight is distributed evenly. The lower the center of gravity the more stable the vehicle, making it easier to control in turns and during quick maneuvers. Civic images from: http://www.budget.com.ph/cars.aspx Chevy image from: http://www.fullsizechevy.com/ Van image from: http://www.freestyletransportation.com/ Retrieved: 10/06/10

A Matter of Balance Vehicle suspension balance refers to the distribution of the weight of the vehicle on the chassis. As you travel a vehicle’s weight shifts from the center of the chassis, to a position where weight is concentrated over the tires. Silver car image from: http://www.autoexpress.co.uk/carreviews/firstdrives/202350/lexus_ls460.html Retrieved: 10/06/10

Weight Distribution A transfer of weight from one point of the vehicle to another occurs whenever the driver: - Accelerates - Brakes - Turns Or a combination of these actions Brown vehicle image from: http://www.aa.co.nz/aadirections/driver/Pages/Self-stopping-car.aspx Blue car image from: http://www.gotbroken.com/search/glow+plugs Red car image from: http://www.autoblog.com/2009/04/15/report-toyota-claims-40-000-pre-orders-for-new-prius/ Retrieved: 10/06/10

Natural Laws Enforce Themselves No matter your age, or what kind of vehicle you drive, natural laws affect your driving. Being aware of these forces will help you be prepared for emergency situations and avoid collisions. Image from: http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr/explaining_motion/forcesandmotionrev1.shtml Retrieved: 09/30/10

Think About It Final Thoughts Due to the Law on Inertia, it’s very important that all passengers wear seat belts while driving. In case of an accident, seat belts provide an opposing force that can prevent a passenger from being thrown out of the vehicle. Windshield image from: http://www.geekologie.com/2007/06/importance_of_seat_belts.php Poster image from: http://www.saferroaduse.nt.gov.au/seatbelts.html Sign image from: http://www.co.jackson.or.us/page.asp?navid=2307 Retrieved: 10/01/10

Test Your Knowledge Often the first thing that changes about you when you drink or use drugs is: Muscle control Steering ability Good judgment Quick reflex movements Answer: C

Test Your Knowledge This sign means: No bicycles allowed Lane is reserved for bicycles only Lane is reserved for motorcycles only Lane is reserved for buses only Answer: B Image from: http://www.cksinfo.com/traffic/roadsigns/regulations/index.html

Test Your Knowledge When you have an accident but the police do not investigate it, a report must be filed with the DMV if anyone was injured (no matter how slightly) or killed: Only if it was your fault Only if you are uninsured No matter whose fault it was If the family of the victim sues Answer: C