Natural Laws and Car Control Chapter 5

Gravity and Energy of Motion n Gravity: force that pulls all things to earth n Effects of driving up and down hills n Center of gravity: point around which objects weight is evenly distributed n Video Video

Energy of Motion n Energy of motion: the energy an object has as it moves (kinetic motion) n Increases dramatically as weight and speed increase

Friction and Traction n Friction: force that keeps the tires on the road n Traction: the friction created by a tire on the road

Tires n Tread and traction – Tread: the grooved surface of a tire that grips the road – Water flow – Tire wear – Penny test n Inflation and traction- proper inflation – ***Temperature affects inflation***

Factors that Reduce Traction n Car Condition – Shocks, tires, steering system n Roadway surface n Surface contact area

Curves n Energy and motion work on car – Which direction does the car want to go? n Car control in curves – Speed – Sharpness of curve – Banked curves – Load

Stopping Distance n Total stopping distance = - Perception time and distance – time and dist. to I.P.D. + Reaction time and distance – time and dist. to E. action +Braking distance – distance from time you apply brakes to stop n EOM will change in proportion to the square of its change in speed. – Ex. When truck speed doubles, it needs 4 X’s the distance to stop. - If you triple your speed, you will need 9 X’s the distance to stop.

5.3 Stopping Distance Estimating Stopping Distance The chart on page 99 shows your reaction distance and braking distance from different speeds. Use the four second rule, which enables you to project your approximate stopping distance under ideal conditions at any speed.

5.3 Stopping Distance Factors that Affect Braking Distance 1.Speed – higher speed – longer distance. 2.Vehicle Condition – worn tires or shocks – longer distance to stop. 3.Roadway Surface – Rain, snow, ice, dirt, etc. reduce traction and increase distance. 4.Driver Ability – If you are distracted or impaired, your will take longer to stop. 5.Antilock Braking System (ABS) – You can better control your stopping distance in curves. 6.Hills – Your braking distance increase downhill. 7.Loads – Heavy loads increase your braking distance.

Force and Impact and Restraint Devices n Force of impact: the force with which a moving object hits another object – Speed – Weight – Distance between impact and stop – 3 collisions in one…..what??? – Video: Fixed ObjectFixed Object

Energy-Absorbing Features n Front and rear crush areas n Energy absorbing bumpers n Side door beams n Reinforced windshield n Energy-absorbing steering wheel and column n Padded dash n Head restraints

Safety Belts and Air Bags n Restraint device – Active restraint – Passive restraint – Child car seat vs. no car seat Child car seat vs. no car seat n Air bags – designed to work WITH belts!!! -VideoVideo n Car Crash Car Crash n Videos on Favorites: Seat belts and speeding