Natural Laws and Car Control
Chapter 5
Gravity
• How will gravity affect your
speed going uphill?
–Lose speed
–to keep same speed you must
accelerate to overcome gravity
Gravity
• How will gravity
affect your speed
going downhill?
– Speed will increase
– Take longer to stop
– Must brake sooner
– Look further ahead
for hazards
Review Gravity
The Law of Gravity
and Hill Parking
When you are parked on an incline,
gravity works to pull your vehicle
downhill.
To keep your vehicle from rolling,
leave your vehicle in low gear or
park.
Wheels to right
Shift to neutral
Roll into curb
Shift to Park
Set Parking Brake
What are the steps?
Downhill with curb
Wheels to right
Shift to neutral
Roll into curb
Shift to Park
Set Parking Brake
What are the steps?
Downhill with curb
TO THE RIGHT
What step do you
skip?
Yes, there is no
curb to roll into.
You’ll be parking downhill with no curb. Which way
will you turn the wheel?
You are already parked uphill without a curb, which way are
your wheels turned?
TO THE RIGHT
Will you put it into neutral and roll?
Again, there is no curb to stop us.
Center of Gravity
• What is it?—The point around which an
objects’ weight is evenly distributed
• Check out pictures on page 92 and 93 in your textbook.
Inflation & Traction
Check out pictures on page 94 & 95
• It is important to have properly inflated tires
because…
– You will have Poor Traction
– Under-inflation (tire not filled up properly)—
outside edges will touch ground and will wear out
faster
– Over-inflation (tire filled up too much)– only
center part of tire is touching ground and will
wear out faster
Total Stopping Distance
pictures on page 98 & 99
• TSD = Distance your car travels while you
make a stop
3 Parts to
total stopping distance
1. Perception time & distance
2. Reaction time & distance
3. Braking distance
Factors affecting braking distance
•
•
•
•
•
•
•
1.
2.
3.
4.
5.
6.
7.
speed
vehicle condition
roadway surface
driver ability
antilock braking system
hills
load (amount of weight in vehicle)
Three factors that determine the
force of impact
1. SPEED—example?
2. WEIGHT—example?
3. DISTANCE BETWEEN IMPACT & STOPPING—example?
Seat Belts
• Three collisions occur when a vehicle hits a solid object.
1. Vehicle hits object & stops
2. Occupants either hit inside vehicle or restraint
devices
3. Occupants may suffer internal collisions when
organs impact inside their bodies
Always wear
your seatbelt!!!