Post on 04-Jan-2016
CHAPTER 5
NATURAL LAWS AND CAR CONTROL
CHAPTER 5
NATURAL LAWS AND CAR CONTROL
5.1 GRAVITY AND ENERGY OF MOTION
5.2 FRICTION AND TRACTION5.3 STOPPING DISTANCE5.4 CONTROLLING FORCE OF IMPACT
GRAVITY : THE FORCE THAT PULLS ALL THINGS TO EARTH
• DRIVING UPHILL:• LOSE SPEED• INCREASE POWER TO OVERCOME GRAVITY
• DRIVING DOWNHILL:• GRAVITY INCREASES SPEED• TAKES LONGER TO STOP• SHIFT TO A LOWER GEAR TO HAVE ENGINE HELP SLOW
VEHICLE
CENETR OF GRAVITY:THE POINT AROUND WHICH AN OBJECTS WEIGHT IS
EVENLY DISTRIBUTED.
LOW CENTER OF GRAVITY=MORE STABLE
High Center of Gravity = Less Stable!
ENERGY OF MOTION
THE FORCE THAT CAUSES OBJECTS TO MOVE.
A.K.A. Kinetic energy
WeightWEIGHT:ENERGY OF MOTION DOUBLES WHEN AN OBJECTS WEIGHT IS DOUBLED.
WHEN IT WEIGHS TWICE AS MUCH IT NEEDS TWICE THE DISTANCE TO STOP
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SPEED:A CAR’S ENERGY OF MOTION WILL CHANGE
IN PROPORTION TO THE SQUARE OF IT’S CHANGE IN SPEED.
EXAMPLE: SPEED GOES FROM 20-40 MPH (IT HAS MULTIPLIED 2X) 2 SQUARED IS 4 SO…………..IT WILL NEED FOUR TIMES THE DISTANCE TO STOP!
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SO ……….IF A CAR SPEEDS UP FROM 20MPH TO 60MPH HOW MUCH HAS THE STOPPING DISTANCE INCREASED?
ANSWER: 9 TIMES
CHAPTER 5FRICTION:
THE FORCE THAT KEEPS EACH TIRE FROM SLIDING ON THE ROAD
TRACTION:IS CAUSED BY FRICTION SO
THAT THE TIRES GRIP THE ROAD
• TIRE TREAD:• GROOVED
SURFACES OF THE TIRE THAT GRIP THE ROAD
DIFFERENT TREADS
A) Off RoadB) Mud!C) RacingD)High Speed/Water
WORN TREAD
= BLOWOUT!
CHAPTER 5INFLATION AND TRACTION:
UNDERINFLATION
OVERINFLATION
CHECKING TIRE TREAD
IF YOU CAN SEE ALL OF LINCOLN’S HEAD, SWITCH THE TIRE
Total Stopping Distance
Perception distance
Reaction distance Braking distance
Oh No There’s a deer!!!!!!
The time it takes to
move your foot
to the brake
The time it takes your brakes to stop your
car
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TOTAL STOPPING DISTANCE=
PERCEPTION TIME +REACTION TIME +BRAKING DISTANCE
VEHICLE CONTROL IN CURVES
FACTORS TO CONSIDER
SPEED
SHARPNESS OF CURVE
BANKED CURVES
LOAD
ENTERING A CURVE
• CAR WANTS TO GO STRAIGHT• THE FASTER YOU GO THE MORE IT
WANTS TO GO STRAIGHT!
Factors That Effect Braking Distance
•Distance
•Speed
•Vehicle Condition
•Roadway surface
•Driver Ability
•Antilock Brakes
•Hills
•Loads
FORCE OF IMPACT FACTORS
SPEEDWEIGHTDISTANCE
BETWEEN IMPACT AND STOPPING
CHAPTER 5SAFETY BELTSACTIVE RESTRAINTS
PASSIVE RESTRAINTS
• AIR BAGS• ATOMATICALLY
DEPLOY WHEN A COLLISION OCCURS
Side Air Bags
HOW TO WEAR YOUR SEATBELT
Comfortable
Low and snug across hips
Shoulder belt should be snug across chest
AIRBAG DISTANCE
MUST HAVE 10 INCHES BETWEEN YOUR CHEST AND THE AIRBAGIN THE STEERING WHEEL
WHY?
HAND POSITION WITH AIRBAG
HERE
AND HERE
WHY?
AIRBAG SWITCHES
AIRBAGS ARE MADE FOR ADULTS
IF A CHILD IS IN THE FRONT SEAT THE AIRBAG MUST BE TURNED OFF
OTHER SAFETY PROTECTION DEVICES
FRONT AND REAR CRASH AREAS
ENERGY ABSORBING BUMPERSREINFORCED WINDSHIELD
HEAD RESTRAINTS
CHILD SEATS
ENERGY ABSORBING STEERING WHEEL AND COLUMN
SIDE DOOR BEAMS
AUTOMATIC SEATBELTS
PADDED DASH