Unseen passage for Class 9 - Passage 05

Posted by Olympiad Tester on


Unseen passage - Did you know that there is a fiber that is as flexible and lightweight as nylon yet five times stronger than steel? Did you know that this fabric is resistant to temperatures higher than 500 degrees Fahrenheit? Did you know that a woman invented this fiber? This miraculous fabric is called Kevlar and it is used to make everything from body armor to musical instruments.

The year was 1964. There were gasoline shortages due to conflict in the Middle East. A PolishAmerican chemist named Stephanie Louise Kwolek was working for DuPont, an American chemical company. She and her group were trying to make a lightweight, yet durable fiber to be used in tires. Lighter tires would allow vehicles to get better gas mileage, but the tires had to be strong enough to resist the wear and tear of the road. They had been working on the problem for some time and had little success, until Kwolek had a breakthrough.

Kwolek and her group were synthesizing or creating fibers to test. During one of the steps in the process, Kwolek created a milky white solution by mixing two chemicals that were often used in the process. This solution was usually thrown away, but Kwolek convinced one of the technicians to help her test it. They were amazed to discover that the fabric that Kwolek had created was not only more durable than nylon, it was more durable than steel. Kwolek had invented Kevlar.

Kevlar is a remarkable fabric known for its strength and durability. Since its invention it has found its way into a wide variety of products. Kevlar is used in sporting equipment like bike tires, bowstrings, and tennis racquets. It is used in musical instruments like drum heads, reeds, and speaker cones. And it is used in protective gear like motorcycle safety jackets, gloves, and shoes. However, Kevlar is best known for its ability to stop bullets.

Richard Armellino created the first Kevlar bulletproof vest in 1975. It contained 15 layers of Kevlar, which could stop handgun and shotgun bullets. The vest also had a steel plate over the heart, which made the vest strong enough to stop rifle rounds. Vests like Armellino's were quickly picked up by police forces and it is estimated that by 1990, half of all police officers in America wore bulletproof vests daily. By 2006 there were over 2,000 documented police vest "saves," or instances where officers were protected from deadly wounds by wearing bulletproof vests.

Kevlar is an amazing fabric not only for its hardness and durability, but also for its heat resistance. Because of this it has been used to replace asbestos. Asbestos is a naturally occurring material that is known for its ability to resist fire. Asbestos can resist temperatures over 1000 degrees Fahrenheit. For this reason it was used in roofs, electrical cables, and brake pads, until people discovered that it causes cancer and other serious health problems. Kevlar poses no such risks. It is lightweight, flexible, and resistant to fire. Therefore, it has proven to be a good replacement for asbestos in many cases.

Since its invention in 1964, Kevlar has won its way into our lives. From musical instruments and brake pads to protective equipment and sporting gear, Kevlar is everywhere. Every day of your life you are exposed to something that was made better by Kevlar. Who'd have known?

Q1) What is Kevlar, and how does it compare to steel in terms of strength?

A. It is a metal alloy; stronger than steel

B. A fabric; more durable than steel

C. A type of plastic; less durable than steel

D. A musical instrument; equally strong as steel

Answer: B. A fabric; more durable than steel

Q2) In what year was Kevlar invented, and what was Stephanie Louise Kwolek's role in its discovery?

A. 1975; she created the first bulletproof vest

B. 1964; she invented Kevlar while working for DuPont

C. 2006; she documented police vest "saves"

D. 1990; she introduced Kevlar to sporting equipment

Answer: B. 1964; she invented Kevlar while working for DuPont

Q3) What motivated the initial research on Kevlar, and what problem were they trying to solve?

A. Gasoline shortages; creating lightweight tires

B. War in the Middle East; developing bulletproof vests

C. Environmental concerns; replacing asbestos

D. Technological advancements; improving musical instruments

Answer: A. Gasoline shortages; creating lightweight tires

Q4) Who created the first Kevlar bulletproof vest, and what materials were used in its construction?

A. Richard Armellino; steel and plastic

B. Stephanie Louise Kwolek; 15 layers of Kevlar

C. DuPont team; asbestos and Kevlar blend

D. Police forces; leather and synthetic fibers

Answer: A. Richard Armellino; 15 layers of Kevlar

Q5) What is the significance of the steel plate in the first Kevlar bulletproof vest?

A. It added weight to the vest

B. It improved flexibility

C. It protected against rifle rounds

D. It made the vest uncomfortable to wear

Answer: C. It protected against rifle rounds

Q6) What role did Kevlar play in the replacement of asbestos, and what advantages does Kevlar offer over asbestos?

A. Kevlar is heavier than asbestos; offers better fire resistance

B. Kevlar has no role in replacing asbestos; similar properties

C. Kevlar is lighter and resistant to fire; replaces asbestos

D. Asbestos is still widely used; Kevlar is not a suitable replacement

Answer: C. Kevlar is lighter and resistant to fire; replaces asbestos

Q7) Apart from bulletproof vests, name two other uses of Kevlar mentioned in the passage.

A. Roofing and electrical cables

B. Musical instruments and bike tires

C. Sporting equipment and brake pads

D. Speaker cones and reeds

Answer: B. Musical instruments and bike tires

Q8) How did Kwolek's discovery of Kevlar impact the production of bulletproof vests?

A. It led to the decline of bulletproof vests

B. It made bulletproof vests heavier and less effective

C. It revolutionized bulletproof vest technology

D. It had no impact on bulletproof vests

Answer: C. It revolutionized bulletproof vest technology

Q9) How has Kevlar contributed to police officers' safety, and when did the use of bulletproof vests become widespread among police forces?

A. Kevlar is ineffective in protecting police officers; never became widespread

B. Kevlar vests have saved officers from deadly wounds; widespread by 2006

C. Kevlar has caused health issues for police officers; not widely adopted

D. Police officers don't use bulletproof vests; a recent development

Answer: B. Kevlar vests have saved officers from deadly wounds; widespread by 2006

Q10) What risks are associated with the use of asbestos, and why is Kevlar considered a safer alternative?

A. Asbestos is lightweight; Kevlar is heavy

B. Asbestos causes cancer; Kevlar poses the same risks

C. Asbestos resists fire; Kevlar is flammable

D. Asbestos causes cancer and health issues; Kevlar is lightweight and safe

Answer: D. Asbestos causes cancer and health issues; Kevlar is lightweight and safe


← Older Post Newer Post →

POST YOUR COMMENT

    1 out of ...
    Sale

    Unavailable

    Sold Out