Numford

MechanicsClass 11, Motion in a Plane

Dimensional formula of Centripetal force

[M L T-2]

SymbolFc SI unitnewton (N)

The inward force mv²/r that keeps a body on a circle. It is a force, so it has the dimension of force.

Derivation

How to get the dimensional formula of centripetal force

  1. Start from the definition: centripetal force = mass × velocity2 / length.
  2. velocity = length / time, so velocity is [L] / [T] = [L T-1].
  3. Put in the dimension of each part: [M] × [L T-1]2 / [L].
  4. Add the powers of each base quantity: [M L T-2].
Same dimensions

Quantities with the dimensions [M L T⁻²]

Equal dimensions do not make them the same quantity. Compare centripetal force with the others in the full grid.

Practice

Three questions on centripetal force

1Which of these has the same dimensions as centripetal force?

2What is the SI unit of centripetal force?

3Which one has different dimensions from the others?

Questions

Centripetal force: quick answers

What is the dimensional formula of centripetal force?

The dimensional formula of centripetal force is [M L T⁻²]. It comes from centripetal force = mass × velocity² / length.

What is the SI unit of centripetal force?

The SI unit of centripetal force is the newton (N).

Which quantities have the same dimensions as centripetal force?

Centripetal force shares [M L T⁻²] with force, tension, thrust, weight. Equal dimensions do not make them the same quantity.

Open the dimensional formula tool