Understanding Stress and Strain

What is the difference between elastic and plastic deformation?

• Elastic deformation is a type of plastic deformation that occurs under stress.

• Plastic deformation can be reversed, while elastic deformation cannot.

• Elastic deformation occurs at high temperatures, while plastic deformation happens at low temperatures.

• Elastic deformation is reversible, while plastic deformation is permanent.

Define tensile stress and provide an example.

• Tensile stress is the pressure applied to a surface; for example, 300 N/m² in a rubber band.

• Tensile stress is the force per unit area in tension; for example, 200 N/cm² in a steel rod under 400 N force.

• Tensile stress is the weight of an object; for example, 50 kg of a concrete block.

• Tensile stress is the bending force on a beam; for example, 150 N in a wooden plank.

What is compressive stress and how does it differ from tensile stress?

• Tensile stress occurs when materials are compressed.

• Compressive stress is only relevant in fluid mechanics.

• Compressive stress is the same as tensile stress.

• Compressive stress is the stress that results from forces pushing together, while tensile stress results from forces pulling apart.

Explain Hooke's Law in your own words.

• Hooke's Law can be expressed as F = kx, where F is the force applied, k is the spring constant, and x is the displacement from the equilibrium position.

• Hooke's Law is only applicable to liquids and gases.

• Hooke's Law describes the relationship between temperature and pressure.

• Hooke's Law states that energy is conserved in a closed system.

What happens to a material when it undergoes elastic deformation?

• The material becomes stronger and more rigid after the stress is applied.

• The material melts and loses its solid form when stress is applied.

• The material returns to its original shape after the stress is removed.

• The material permanently deforms and does not return to its original shape.

Describe a real-world application of tensile stress.

• The design of suspension bridges, where cables experience tensile stress.

• The operation of hydraulic presses, which rely solely on compressive forces.

• The manufacturing of rubber bands, which only experience shear stress.

• The construction of skyscrapers, where beams are only compressed.

What is the significance of the yield point in stress-strain diagrams?

• The yield point represents the temperature at which a material begins to melt.

• The yield point signifies the stress level at which a material begins to deform plastically, marking the transition from elastic to permanent deformation.

• The yield point is the point where a material returns to its original shape after stress is removed.

• The yield point indicates the maximum stress a material can withstand before breaking.

How does temperature affect the stress-strain relationship of materials?

• Temperature only affects the electrical properties of materials.

• Temperature has no effect on material properties.

• Temperature influences the mechanical properties of materials, affecting their ductility and strength.

• Higher temperatures always increase material strength.

What is the formula for calculating tensile stress?

• Tensile Stress = F / A

• Tensile Stress = A / F

• Tensile Stress = F + A

• Tensile Stress = F * A

Explain the concept of strain in the context of material deformation.

• Strain is the total force applied to a material.

• Strain refers to the temperature change in a material.

• Strain is the ratio of change in length to the original length of a material under stress.

• Strain is the weight of a material divided by its volume.