Dimensional Formulas:
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Stress (σ) is the force per unit area applied to a material, while Young's modulus (E) is a measure of the stiffness of a solid material, defined as the ratio of stress to strain.
Both stress and Young's modulus share the same dimensional formula:
Where:
Explanation: This dimensional formula arises from the fundamental definitions of stress (force/area) and Young's modulus (stress/strain, where strain is dimensionless).
Stress Derivation: Stress = Force/Area = (Mass × Acceleration)/Area = [M][LT⁻²]/[L²] = [M L⁻¹ T⁻²]
Young's Modulus Derivation: Young's modulus = Stress/Strain = [M L⁻¹ T⁻²]/[dimensionless] = [M L⁻¹ T⁻²]
Tips: Enter the powers for mass (M), length (L), and time (T) dimensions. The calculator will verify if your input matches the standard dimensional formula for stress or Young's modulus.
Q1: Why do stress and Young's modulus have the same dimensions?
A: Because Young's modulus is defined as stress divided by strain, and strain is a dimensionless quantity (length/length).
Q2: What are the SI units for stress and Young's modulus?
A: Both are measured in Pascals (Pa), which is equivalent to N/m² or kg/(m·s²).
Q3: Can dimensional formulas be used for unit conversion?
A: Yes, dimensional analysis is fundamental for converting between different unit systems and verifying equation consistency.
Q4: What other physical quantities share this dimensional formula?
A: Pressure, energy density, and modulus of rigidity all share the [M L⁻¹ T⁻²] dimensional formula.
Q5: Why is dimensional analysis important in physics?
A: It helps verify equations, derive relationships, convert units, and understand the fundamental nature of physical quantities.