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 TRACTION
5.3 STOPPING DISTANCE
5.4 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
A.K.A. Kinetic energy
THE FORCE THAT CAUSES
OBJECTS TO MOVE.
Weight
WEIGHT:
ENERGY OF MOTION DOUBLES WHEN
AN OBJECTS WEIGHT IS DOUBLED.
WHEN IT WEIGHS TWICE AS MUCH IT
NEEDS TWICE THE DISTANCE TO STOP
CHAPTER 5
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!
CHAPTER 5
SO ……….
IF A CAR SPEEDS UP FROM 20MPH
TO 60MPH HOW MUCH HAS THE
STOPPING DISTANCE
INCREASED?
ANSWER: 9 TIMES
CHAPTER 5
FRICTION:
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 Road
B) Mud!
C) Racing
D) High Speed/Water
WORN TREAD
= BLOWOUT!
CHAPTER 5
INFLATION AND TRACTION:
UNDERINFLATION
OVERINFLATION
CHECKING TIRE
TREAD
IF YOU CAN SEE ALL OF LINCOLN’S HEAD,
SWITCH THE TIRE
Total Stopping Distance
Oh No
There’s a
deer!!!!!!
The time
it takes to
move your
foot to
the brake
Perception
distance
Reaction
distance
The time it
takes your
brakes to
stop your
car
Braking distance
CHAPTER 5
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
SPEED
WEIGHT
DISTANCE
BETWEEN IMPACT AND
STOPPING
CHAPTER 5
SAFETY BELTS
ACTIVE 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
AND
HERE
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 BUMPERS
REINFORCED WINDSHIELD
HEAD RESTRAINTS
CHILD SEATS
ENERGY ABSORBING STEERING
WHEEL AND COLUMN
SIDE DOOR BEAMS
AUTOMATIC SEATBELTS
PADDED DASH