Numford

Properties of matterClass 11, Mechanical Properties of Fluids

Dimensional formula of Pressure gradient

[M L-2 T-2]

SI unitpascal per metre (Pa/m)

How fast the pressure changes with distance. It drives the flow of a fluid.

Derivation

How to get the dimensional formula of pressure gradient

  1. Start from the definition: pressure gradient = pressure / length.
  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. Put in the dimension of each part: [M L-1 T-2] / [L].
  8. Add the powers of each base quantity: [M L-2 T-2].
Practice

Three questions on pressure gradient

1Which is the dimensional formula of pressure gradient?

2What is the SI unit of pressure gradient?

3Do pressure gradient and Young's modulus have the same dimensions?

Questions

Pressure gradient: quick answers

What is the dimensional formula of pressure gradient?

The dimensional formula of pressure gradient is [M L⁻² T⁻²]. It comes from pressure gradient = pressure / length.

What is the SI unit of pressure gradient?

The SI unit of pressure gradient is the pascal per metre (Pa/m).

Is pressure gradient dimensionless?

No. Pressure gradient has the dimensions [M L⁻² T⁻²].

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