Numford

MechanicsClass 11, Work, Energy and Power

Dimensional formula of Coefficient of restitution

[M0 L0 T0]

Symbole SI unitnone, a pure number

The ratio of speed of separation to speed of approach in a collision. It is a pure number between 0 and 1.

Derivation

How to get the dimensional formula of coefficient of restitution

  1. Start from the definition: coefficient of restitution = velocity / velocity.
  2. velocity = length / time, so velocity is [L] / [T] = [L T-1].
  3. Put in the dimension of each part: [L T-1] / [L T-1].
  4. Add the powers of each base quantity: [M0 L0 T0].
Same dimensions

Quantities with the dimensions [M⁰ L⁰ T⁰]

Equal dimensions do not make them the same quantity. Compare coefficient of restitution with the others in the full grid.

Practice

Three questions on coefficient of restitution

1Which of these has the same dimensions as coefficient of restitution?

2Which of these has no dimensions at all?

3Which one has different dimensions from the others?

Questions

Coefficient of restitution: quick answers

What is the dimensional formula of coefficient of restitution?

The dimensional formula of coefficient of restitution is [M⁰ L⁰ T⁰]. It comes from coefficient of restitution = velocity / velocity.

What is the SI unit of coefficient of restitution?

Coefficient of restitution has no unit, because it is a pure number.

Is coefficient of restitution dimensionless?

Yes. Coefficient of restitution is a ratio of like quantities, so every power in its dimensional formula is zero: [M⁰ L⁰ T⁰].

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