Which material is known for having a high strength-to-weight ratio among common engineering materials?

• A. Concrete
• B. Glass fiber
• C. Carbon fiber
• D. Plywood

Answer: (C)

A material's strength-to-weight ratio, also called specific strength, is a key factor in lightweight structural design. Carbon fiber excels here because it combines very high tensile strength with a relatively low density, giving a much higher specific strength than most common engineering materials. That means it can carry large loads without adding much weight, which is why it’s favored for aircraft, high-performance cars, and other applications where weight matters.

Concrete, while strong under compression, is heavy and relatively weak in tension, so its strength-to-weight ratio isn’t high. Glass fiber has good strength and is light, but its specific strength is typically not as high as carbon fiber. Plywood is a wood-based material with moderate strength and greater density than carbon fiber, resulting in a lower strength-to-weight ratio.

So, carbon fiber is the best choice for a high strength-to-weight ratio among these common engineering materials.