1. Activity 84 Analysis
Choose one of the safety features described in the reading. Use the terms inertia, force, and deceleration to describe how the safety feature helps keep people safe in a collision.
on impact, the car decelerates rapidly
inertia keeps objects within the car (including people) moving at a higher speed
Describe how your chosen safety features decelerates the body more gradually so that there is an increase in time and a reduction in force.

2. As a collision is about to happen, if you had enough time to chose between hitting a large haystack or a telephone pole, which one would you choose to hit? Explain why in terms of force and deceleration.
The haystack
telephone pole is more rigid (and attached) resulting in ____ impact force
area for impact of haystack is _____
force from haystack is decreased because…..

3. In the accident mentioned in Activity 73, “Choosing a Safe Vehicle,” Noah’s family car had old tires that were worn down. Explain how this could have contributed to the car accident.
Tires are designed to optimize friction between the tires and the road
The car gets:
good traction
handles well
can stop quickly
describe what happens as tires wear down

4. Reflection: Since the 1920’s, the rate of fatalities per billion miles traveled has dropped steadily. However, the rate has been about the same for the past 20 years. Why do you think this is?
Include ideas about:
major gains in safety features occurred before/after the rate settled
more distraction on the road
minimum number of “bad” drivers will stop it from dropping indefinitely
weather & other factors keep it from continuing to decline

5. Some factors that tend to keep fatality rates the same are:
more distractions, such as cell phones and handheld electronic devices
a larger number of older drivers
lack of seatbelt use (almost 40% of all passengers killed are not wearing seatbelts)
reintroduction of higher speed limits
less car uniformity (mass, bumper height) when vehicles collide

6. Activity 84 Major Concepts
Technology influences society through its products and processes. It influences quality of life and ways people act and interact.
Some devices can decrease injuries and fatalities in more than one way. Seatbelts help reduce the collision force by increasing the area of the force across a person’s body, redirecting the force from the head to the broader torso, and by decelerating the body over more time than if it hit the steering wheel or dashboard.

7. Read E-58

8. Activity 86 Title: Investigating Center of Mass
Problem: How does the center of mass affect what happens in a collision?
Hypothesis: If _____, then __________.

9. In this activity you will investigate the similarities and differences between mass and center of mass in the context of car accidents.
Center of mass, sometimes called the center of gravity, is the point at the center of an object’s (or system’s) distribution of mass. It is also the point around which the object balances
While mass is the total amount of matter or “stuff” in an object, the center of mass describes the location around which the mass is equally distributed.

10. Determining the center of mass of irregularly shaped objects and objects made from a variety of materials, such as cars, can be difficult.
Most often the center of mass is found inside the object, such as in the chassis of a car.
The center of mass can be found outside its shape, such as in a boomerang that has a center of mass in between its two shaped arms.

11. Have you heard of a rollover accident?
Common in single vehicle accidents when
-a vehicle swerves
-hits a relatively immobile barrier (such as a guardrail)
-becomes unbalanced when it goes around a sharp curve.
Rollover accidents make up 3% of accidents, but account for 33% of accident fatalities. They have the highest fatality rate of any type of accident.

12. Read the procedure on pages E-59 to E-60
The two loaded carts have the same mass.
The relative position of the heavier metal cylinder determines the center of mass.
Pay attention to procedure steps that require predictions (steps 6 and 9)! Write the step number and predictions below your table.

13. Observations & Stability Rating
Did the rear wheels come off the ground? If so, how far?
Did the wheels come off the track?
Did the cart tip over?
Stability Rating: Use 1-3
1 = most stable, 3 = least stable

14. Compare results before beginning analysis questions
The results of the loaded-cart investigation can only be applied to the situation of a single car colliding with a fixed barrier.
How might accidents on a real road be different?

15. Auto Accidents SUV Rollover Accident Injury Lawsuits and Litigation
SUVs were originally designed as work vehicles and most are still built using a truck chassis. Never intended as passenger vehicles, SUVs feature a high profile and narrow track that makes them very rollover-prone. With their weak roofs and poor crash protections, SUVs roll over with enough frequency to account for sixty percent of the more than 10,000 rollover fatalities in the U.S. every year.