Chapter 5 Natural Laws and Car Control

Gravity What is gravity? the force that pulls things towards the earth the force that pulls things towards the earth How does gravity affect you when driving? uphill/downhill driving- shift to a lower gear uphill/downhill driving- shift to a lower gear What is the “center of gravity”? the point at which an objects weight is evenly distributed the point at which an objects weight is evenly distributed How does center of gravity affect your car and its driving ability? How will driving uphill and downhill affect your stopping distance? Which vehicle to the right has the fastest stopping ability? why? High Center of Gravity Low Center of Gravity

Energy of Motion and Stopping Distance What 2 things make up energy of motion? (how an object moves) Depends on speed and weight Depends on speed and weight How does speed affect stopping distance? SQUARE the change in speed- for example: SQUARE the change in speed- for example: double the speed = 4 times distance to stop (60 ft) double the speed = 4 times distance to stop (60 ft) triple the speed = 9 times distance to stop (135 ft) triple the speed = 9 times distance to stop (135 ft) How does weight affect stopping distance? Double the weight= 2 times distance to stop Double the weight= 2 times distance to stop SPEED WEIGHT

Total Stopping Distance Perception Distance= the distance you travel while identifying a situation Perception Distance= the distance you travel while identifying a situation+ Reaction Distance= the distance you travel from the time you identify a hazard and decide to brake + Braking Distance= the distance you travel from the time you first apply the brakes to a full stop

Braking Distance List 7 factors that affect braking distance- speed speed vehicle condition vehicle condition road surface road surface driver ability driver ability ABS ABS Hills Hills Load Load

Traction and Friction What controls your car? steering wheel steering wheel brake pedal brake pedal accelerator accelerator 4 tires- most important 4 tires- most important What is friction? friction? The gripping action that keeps the tire from slipping What is tread? Allows water to flow away from the tire Allows water to flow away from the tire How can you check for TREAD WEAR on your tires? How can you check for TREAD WEAR on your tires? What affects your cars traction? What affects your cars traction?tread inflation of tires

Tire Inflation More of the tire is touching the surface Outer edges of the tire are touching the surface- where would you find the most wear and tear? Center of tire is touching the surface- where would you find the most wear and tear?

Banked Curve What is a BANKED CURVE? A road built higher on the outside than on the inside to keep cars on the road! A road built higher on the outside than on the inside to keep cars on the road! Where else would you find a BANKED CURVE? Roller Coasters Race Track

Motorcycle vs Car Force of Impact = speed + weight + dist traveled

Controlling the Force of Impact How hard one moving object hits another object = force of impact Speed + Weight+ Distance traveled = force of impact The most important factor in determining how hard an object hits is? SPEED- slow down! What safety features on cars can help control the force of impact? Show Crash Physics Video

SEAT BELT USAGE 3 collisions occur in a crash- what are they? Turn to the person next to you and discuss if YOU THINK THERE SHOULD BE A SEATBELT LAW REQUIRING YOU TO WEAR A SEATBELT? WHY OR WHY NOT? Show seatbelt video

Active Restraints Until what age do children have to be in some sort of car seat? safety belts car seats

Passive Restraints head restraints head restraints air bags air bags bumpers bumpers side door beams side door beams reinforced windshield reinforced windshield steering column steering column padded dash padded dash

Side Impact Collision Safety features?

Crazy Cats

Motorcycle Dog

I DON’T WEAR A SEAT BELT BECAUSE… I am driving at low speeds most of the time I might be saved if I am thrown from the car I might be trapped in a burning or submerged car I only drive for short trips to stores, school or work I always ride in the front seat and can brace myself against the instrument panel I don’t think safety belts reduce my chances of being injured in a collision