1. 4.4 and 4.5 Applications to automobiles, sports and research
p read and make notes on :
Car tires, car breaks, electronic stability controls, crash testing, airbags, golf club design, footwear design,

5. Section 4.4
Forces Applied to Automotive Technology
One seat belt design pulls the passenger into an optimal crash position after a computer detects a crash or a strong, sudden stop. The animation shows the piston going up and turning the rack gear, which pulls in the seat belt.

6. Section 4.4
Discussion: Forces Applied to Automotive Technology
Why were earlier seat belt designs harmful to passengers? Discuss how the design shown here is less harmful.

7. Section 4.4
Answers for Discussion Questions:
Sample answer: Earlier seat belt designs hurt passengers because the seat belt applied huge forces on the passenger during the crash or stop. The design shown in the animation, called a pretensioner, reduces the applied force by reeling in the seat belt, which puts the passenger in a less dangerous position for the crash.

8. Using the terms below, label each circled area of the images.
Section 4.5
Forces Applied to Sports and Research
Using the terms below, label each circled area of the images.
decrease force of kinetic friction
increase coefficient of static friction
increase force of static friction

9. Section 4.5
Discussion: Forces Applied to Sports and Research
For each sport illustrated here, discuss the advantage or purpose of adjusting the force or friction coefficient.

10. Using the terms below, label each circled area of the images.
Section 4.5
Forces Applied to Sports and Research
Using the terms below, label each circled area of the images.
increase force of static friction
increase coefficient of static friction
decrease force of kinetic friction

11. Section 4.4
Answers for Discussion Questions:
Sample answer: The golf grip is made of rubber or leather. These materials increase the force of static friction between the club and the golfer’s hands. By increasing the force of static friction, it is more difficult for the hands to slip, thus allowing the golfer more control. When skating, it is preferable to reduce the force of kinetic friction so that the skater can move faster and more easily. When running, the runner does not want to slip and possibly cause injury, so the soles are designed to increase the coefficient of static friction.

12. Section 4.6
All-Season Tires versus Snow Tires
Compare all-season tires and snow tires by completing the table using the terms below.
All-Season Tires
Snow Tires
How are they similar?
How are they different?
temperature
weather conditions
logo
snow crystal
all conditions
colder temperatures
prevent hydroplaning
no logo
snow and ice
provide traction
all temperatures

13. Section 4.6
All-Season Tires versus Snow Tires
Compare all-season tires and snow tires by completing the table using the terms below.
All-Season Tires
Snow Tires
How are they similar?
prevent hydroplaning
provide traction
How are they different?
all temperatures
temperature
snow and ice
all conditions
weather conditions
colder temperatures
no logo
logo
snow crystal