Inertia 2 rules of inertia –1. objects move in a straight line unless some force is put upon them –2. objects at rest stay at rest.
The force that pulls objects to the center of the earth.
Uphill Must increase speed because gravity works against you.
Going Up Hill Gravity Have to hit gas to get uphill
Downhill Must decrease speed because gravity works with you.
Going Downhill Gravity working with you; have to slow down or risk losing control
The point around which an object’s weight is evenly balanced.
--The energy an object has as a result of motion. -- It is the actual force created by movement.
Two factors that affect energy of motion. SPEEDWEIGHT
The higher the SPEED and WEIGHT the more energy of motion.
Which has the greatest effect? SPEED
Force between 2 surfaces that resists the movement of one surface against the other. Examples--- –Socks on carpet versus socks on waxed floor.
The friction, or gripping action, between the roadway and tire.
Tread The grooved surface of a tire that grips the roadway.
Factors that Affect Tire Condition There are 4 factors that affect tire condition and, more importantly, its ability. 1. Condition 2. Rain Snow/Ice Road Conditions—potholes, construction, etc.
Purpose To remove water from in front of the tire.
Over inflation Only center of the tire will grip the road properly.
Under inflation Only the edges of the tire will grip the road properly.
Proper inflation The tire grips the road evenly and causes even tread wear.
Proper Tire Inflation
Straight line All traction is used to slow down or speed up the vehicle.
Slowing/Turning Some traction is used to slow. Most traction is used to turn.
Turning/Accelerating Most traction is used to turn. Some traction is used to accelerate.
Two forces that work on a vehicle in a curve. Energy of motion Traction
Energy of motion The energy of motion in your vehicle will try to make it go in a straight line.
Traction If traction limit is exceeded in curve, vehicle will begin to skid.
4 factors to negotiate curves Speed Sharpness Load Banked curves
Speed Slow for turns before the turn.
The sharper the turn, the slower the car. Right turns are sharper than lefts. Sharpness
The heavier the vehicle the slower it must travel. Load
Banked Curves Curves that are higher on the outside than on the inside.
The time/distance it takes a driver to identify a hazard and come to a complete stop. ________________________________________________________________________________________________________ Perception Reaction Braking
The time and distance it takes a driver to identify, predict, and decide to slow for a hazard.
The time/distance it takes a driver to react to a hazard. Average reaction time= ¾ of a second
The time/distance your vehicle travels from the time the brakes are applied until you stop.
Stopping Distance
The force at which a moving object hits another object.
Momentum A vehicle’s momentum(how fast/slow an object is moving) is determined by its’ weight and speed. Higher Momentum = More Damage
Speed Weight Distance between impact and stop
The faster the speed, the greater the force of impact.
Adjusting speed to Highway Conditions 3 situations in which you should change your speed(SLOWER): –1. Visibility decreases –2. Traction decreases –3. Loss of space around your car.
When you should adjust Location of other vehicles—if you lose space around any part of your car, you may need to speed up or slow down. If you break the safe following distance(which is 2 car lengths or 2-4 seconds) Always SPEED UP when changing lanes.
The heavier the vehicle, the greater the force of impact.
The shorter the distance, the greater the force of impact.
1. Vehicle hitting an object. 2. Occupants hitting something inside the vehicle. * Object inside vehicle hitting occupants. 3. Organs hitting body cavity.
Hold occupants in place during collision.
A restraint device the occupant must put on themselves. Ex.- Seatbelt Active Restraint
A restraint device that works automatically. Ex.- Air bags Passive Restraint
Seatbelt Law Click it or Ticket