Chapter 5 Natural Laws & Car Control

Gravity Gravity- Pulls all objects toward the center of the earth. When driving downhill, gravity speeds you up. When driving uphill, gravity slows you down. Center of Gravity- The point around which all of a car’s weight is evenly balanced. A low center of gravity is better for a car.

Energy of Motion The energy an object has when it’s moving. Energy of motion increases greatly with increases of speed and weight. (pg. 93)

Friction / Tires Keeps the tires from slipping Tires control the movement of the car. Friction = Traction Tread- the grooved surface of the tire that touches the road. The deeper the tread, the better the traction Split traction – Speed, Braking and Turning

Factors that reduce traction Poor Car Conditions Worn steering system Poor shock absorbers Tire wear- major cause of reduced traction Poor road Surfaces Slick roads Sand, mud, or gravel roads

Curves Cars want to go straight through curves. Factors that affect control in a curve Speed- slow down before you get to the curve Sharpness of a curve Bank of a curve Load

Stopping Distance Total Stopping Distance- Distance it takes to stop, from the time you see a problem until you come to a complete stop. Perception Time and Distance Reaction Time and Distance-average reaction time ¾ second. Braking Distance

Factors that Affect Braking Distance Speed Condition of Car Road Surface Driver Ability Hill Load

Impact Factors Affecting Impact Speed Weight Distance Between Impact and Stop You’re better off if something slows you down gradually

Ways to Protect Passengers Restraint Devices Passive Active Safety Belts Three collisions- car you and internal organs

Ways to Protect Passengers Air Bags Use with safety belts Use balanced hand position to avoid facial injury Put children in back seat Airbag Improvements Adjustable speed On/Off switches

Other Protective Devices Front and rear crush areas Side door beams Reinforced windshields Energy absorbing steering wheel and column Padded dash Energy absorbing bumpers Child safety seats

Homework Study for Chapter 5 Test