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

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 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

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

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