Numford

Properties of matterClass 11, Mechanical Properties of Solids

Dimensional formula of Compressibility

[M-1 L T2]

Symbolκ SI unitper pascal (Pa⁻¹)

The inverse of the bulk modulus. It tells how much a material shrinks under pressure.

Derivation

How to get the dimensional formula of compressibility

  1. Start from the definition: compressibility = 1 / bulk modulus.
  2. velocity = length / time, so velocity is [L] / [T] = [L T-1].
  3. acceleration = velocity / time, so acceleration is [L T-1] / [T] = [L T-2].
  4. force = mass × acceleration, so force is [M] × [L T-2] = [M L T-2].
  5. area = length × length, so area is [L] × [L] = [L2].
  6. pressure = force / area, so pressure is [M L T-2] / [L2] = [M L-1 T-2].
  7. strain = length / length, so strain is [L] / [L] = [M0 L0 T0].
  8. Put in the dimension of each part: 1 / [M L-1 T-2].
  9. Add the powers of each base quantity: [M-1 L T2].
Practice

Three questions on compressibility

1Which is the dimensional formula of compressibility?

2What is the SI unit of compressibility?

3Do compressibility and pressure gradient have the same dimensions?

Questions

Compressibility: quick answers

What is the dimensional formula of compressibility?

The dimensional formula of compressibility is [M⁻¹ L T²]. It comes from compressibility = 1 / bulk modulus.

What is the SI unit of compressibility?

The SI unit of compressibility is the per pascal (Pa⁻¹).

Is compressibility dimensionless?

No. Compressibility has the dimensions [M⁻¹ L T²].

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