1. Unit 5: Natural Laws and Car Control in Adverse Conditions
NV Driver Education Curriculum
Unit 5: Natural Laws and Car Control in Adverse Conditions
Presentation 1 of 6
TOPICS:
Inertia
Momentum
Gravity

2. What are Natural Laws?
Natural laws are forces in nature that are always at work.
Those that affect you as a driver are:
Inertia
Gravity
Friction
Momentum
Kinetic Energy
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Retrieved: 09/30/10
In an emergency, these natural laws can work for or against you.

3. Inertia
Objects at rest do not move unless an outside force acts on them. Parked cars stay parked.
An object in motion continues to move straight ahead until acted upon by some outside force.
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Moving image from:
Retrieved: 09/30/10
Moving cars continue to move without acceleration.

4. Feeling Inertia
You experience inertia when you accelerate, decelerate, or drive around a sharp curve.
Images From: Driver Right textbook 11th Edition
Retrieved: 09/30/10
Acceleration Deceleration In a Curve .

5. Five Factors that Effect Inertia
Sharpness of a turn or curve
Speed of vehicle
Size, height, weight and load of vehicle
Roadway slope
Roadway surface condition
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Truck on wet road image from:
Retrieved: 10/06/10

6. Momentum
Momentum is inertia in motion. The momentum of a moving object depends on its mass (weight) and velocity (speed).
A large dump truck traveling at 50 mph has more momentum than a small passenger car or motorcycle traveling at the same speed.
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Motorcyclist image from:
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7. Understanding Crashes
The greater the momentum, the greater the damage in a collision. As your speed increases, so does the vehicle’s momentum and the likelihood of damage in case of a collision.
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Red car image from:
Retrieved:10/06/10
Speeding vehicles cause extensive damage.
Heavier vehicles cause more damage.

8. Essentially, people get injured due to excessive acceleration.
Physics of Crashes
Essentially, people get injured due to excessive acceleration.
Even though the two vehicles have the same speed and the same final speed, the smaller car changes speed AND direction, thus having a much greater acceleration.
In order to decrease the acceleration of the car (and the people inside) one must increase the distance (and thus time) over which the collision takes place.
Images from:
Retrieved: 10/06/10

9. Crash Test Videos Click on web address to access video clips
Insurance Institute for Highway Safety (IIHS)
Crash with and without
Seatbelt and Airbag
(0:17) real player
Insurance Institute for Highway Safety (IIHS)
Safety Consequences
Size and Weight
(2:33) real player
Always preview video before showing to students
Check content
Check availability
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IIHS image from:
Retrieved: 01/21/10
YouTube image from:
Click on web address to access video clips
*Suggest full screen viewing

10. Kinetic energy is the energy of motion, not the motion itself.
The more kinetic energy a vehicle has, the more time and distance it will take to stop.
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11. Effect of Speed and Weight
A vehicle’s energy of motion changes in proportion to the SQUARE (x2) of the change in speed.
Double (2x) your speed and your vehicle will:
have four times (22) as much energy of motion
need four times (22) as much distance to stop
Image from: drive Right textbook 11th Edition
Retrieved: 09/30/10

12. Gravity
Gravity is a force that pulls objects towards the center of the earth. On hills gravity makes a vehicle: - slow down when going up hill - speed up when going down hill
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Images from:
Retrieved: 10/06/10

13. Center of Gravity
The center of gravity is a point in the center of the vehicle where the weight is distributed evenly.
The lower the center of gravity the more stable the vehicle, making it easier to control in turns and during quick maneuvers.
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14. A Matter of Balance
Vehicle suspension balance refers to the distribution of the weight of the vehicle on the chassis.
As you travel a vehicle’s weight shifts from the center of the chassis, to a position where weight is concentrated over the tires.
Silver car image from:
Retrieved: 10/06/10

15. Weight Distribution
A transfer of weight from one point of the vehicle to another occurs whenever the driver:
- Accelerates
- Brakes
- Turns
Or a combination of these actions
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Red car image from:
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16. Natural Laws Enforce Themselves
No matter your age, or what kind of vehicle you drive, natural laws affect your driving.
Being aware of these forces will help you be prepared for emergency situations and avoid collisions.
Image from:
Retrieved: 09/30/10

17. Think About It
Final Thoughts
Due to the Law on Inertia, it’s very important that all passengers wear seat belts while driving. In case of an accident, seat belts provide an opposing force that can prevent a passenger from being thrown out of the vehicle.
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18. Test Your Knowledge
Often the first thing that changes about you when you drink or use drugs is:
Muscle control
Steering ability
Good judgment
Quick reflex movements
Answer: C

19. Test Your Knowledge This sign means: No bicycles allowed
Lane is reserved for bicycles only
Lane is reserved for motorcycles only
Lane is reserved for buses only
Answer: B
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20. Test Your Knowledge
When you have an accident but the police do not investigate it, a report must be filed with the DMV if anyone was injured (no matter how slightly) or killed:
Only if it was your fault
Only if you are uninsured
No matter whose fault it was
If the family of the victim sues
Answer: C