5.1. Chapter 5. Is the force that pulls all things to Earth. Gravity and Energy of Motion. Driving Up Hills. Driving Down Hills

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1 Chapter 5 Natural Laws and Car Control 5.1 Gravity and Energy of Motion Is the force that pulls all things to Earth. Driving Up Hills You will speed unless you use extra power To hold speed You must the vehicle s s power to overcome the pulling force of gravity Easier to! Driving Down Hills Gravity will your speed while going down hill. Will take you longer to! Always while going down a hill! of Is the point around which an object s weight is distributed. Lower the center of gravity the stable the object becomes. SUVs very especially when you lift them. *Car carriers! 1

2 of The energy or the energy an object has because it is moving. The faster your vehicle moves, the energy of motion it has. Energy of motion is also affected by the of the moving object. Energy of Motion and Stopping Distance Go to page 93. When a truck weighs twice as much; it needs about the distance to STOP! 5.2 Friction & Traction Is the force that keeps each tire from on the road. You can feel the same force by rubbing your hands together. Friction or gripping power between the and the roadway surface. Traction makes it possible for your vehicle to the road so you can change speed and direction. TIRES!!!! Tires make a huge difference in the way your vehicle performs. Driving with low pressure in your tires can be the difference between avoiding a collision or hitting something. We will discuss this very soon! 2

3 Tread and Traction - outer grooved surface of a tire that grips the road. Tread allows the tire to cut through and grip the road. Bald tires grip the road More likely to have a blowout. Is where all the air escapes a tire at once. See page 95 Inflation and traction Always check the owner s s manual to find out the best air pressure range to keep your tires at! Check regularly! Cold weather pressure Hot weather pressure Underinflation Only the of the tires will grip the ground. Outside part of tires will wear first which equally short life of the tires. In emergencies it will not perform properly. Overinflation Only the of the tire will grip the road. The center of the tire will wear more quickly than a normal tire. Reduced Traction Vehicle s s condition 3

4 When are the road most slippery? Curves Energy of motion and traction will work on your vehicle as you go around a curve. The energy of motion will try to make your vehicle go in a curve. the speed = more it will tend to go straight. Speed and Curves You cant control the but you can control your. Reduce your chances of skidding by your speed before entering a curve. Sharpness of Curves The sharper a curve, the more traction your vehicle needs to grip the road. Sharper the curve = your speed Banked Curves A curve that is on the outside than it is on the inside. Helps to overcome your vehicle's tendency to move to the outside of the curve. 5.3 Stopping Distance 4

5 Distance The distance your car travels while you make a stop. Time The it takes to The it takes to identify, predict, and decide to slow for a hazard. Perception time will vary depending on: The of hazard Perception The your vehicle travels during perception time. Depending on the driving situation this may change. Time The length of time you take to execute your action. Average reaction time is of a second. Distance The distance your vehicle travels while you react. Distance The distance you vehicle travels from the time you the brake until your vehicle. * If you accelerate from 20 mph to 40 mph, your braking distance will be about times longer. 5

6 How do you estimate stopping distance? Pick a fixed object or checkpoint ahead where you think you can stop. Count seconds. Check your position. If you reached it, then you can assume that you could have stopped there under ideal conditions. *If you were traveling 65 mph, it would take about 300 ft to stop (length of a football field.) Factors that Affect Braking Distance higher speed Speed higher speed the braking distance Vehicle Condition vehicles with worn shocks,,, and brakes need longer time rain,, Roadway surface rain, ice, dirt, gravel, & reduce traction Driver Ability if you are distracted or impaired, it will take you longer to stop your vehicle. Antilock Braking System allows you to better control your stopping distance while turning braking when Hills braking driving downhill Loads loads increase Loads your braking distance 5.4 Controlling Force of Impact Force of Impact The force with which a Three factors that determine how hard something will hit another object: Speed Is the factor in Is the factor in determining how hard a vehicle will hit another object. Any reduction in speed will greatly the damage inflicted. Always try to speed in Always try to an emergency. 6

7 Weight The heavier a vehicle, the damage it will cause in a collision. A vehicle weighing twice as much as another vehicle will hit a solid object as hard. as hard. Distance between impact & stopping The a vehicle covers between the instant it hits an object and the moment it comes to a can vary greatly. Sand barrels slow your vehicle as it hits a guardrail. How many collisions occur when you are in a collision? 1 st The hits the object and stops. 2 nd The either hit the inside of the vehicle or their restraints devices. 3 rd Occupants may suffer internal collisions as their organs their bodies. Passive Restraints Devices Works Ex. Active Restraint Devices Is a device that you have to. Ex. How to wear safety belts 1. Adjust your seat to a comfortable upright position. 2. Buckle your seatbelt making sure lap part is low and snug across your hips. 3. Adjust shoulder part. Never put it behind your body! 7

8 Air Bags Is balloon-type device that automatically inflates to protect you. They deploy at speeds over mph. Are designed to work with. Keep hands between 9 and 3 o clock o and 8 and 4 o clock o to prevent serious hand, arm, head, and eye injury. Airbags continued Make sure you sit at least inches away from the steering wheel. Children in child seats and young people up to the age of must sit in the back seat. Air bag Improvements Sensors can measure weight, seat position, and severity of crash. Deploys in 2 stages appropriate for speed and intensity Airbag switches give vehicle owners a choice about using an airbag. Other Protection Devices Automatic Safety Belts Make sure you buckle the lap belt Front and rear crush areas Designed to on impact like an accordion Energy absorbing bumpers Absorb low levels of impact up to mph without damage Side door beams Steal beams built into the side door. windshield Two pieces of glass with a thin layer of plastic in the middle help avoid flying glass. Energy-absorbing steering wheel Designed to when hit. dash Can reduce injury in all crashes seats All states require them. Must be used in the back seat. Head restraints Padded head rests on top of seat protect against. 8

9 GOOD LUCK on Tuesday or Thursday 9

Drive Right Chapter 5 Study Guide

Drive Right Chapter 5 Study Guide 3/23/2008 Define Gravity. Define Center of Gravity. Define Energy of Motion Define Friction. Define Traction. How does gravity affect your car going uphill? What is Tread, and how is it affected when the