RELATIONSHIP between DIFFERENT physical quantities.For example, Dimensional Formula for work DONE and Kinetic Energy is the same. So, we can say they are related.For dimensionless quantities, dimensional analysis can't be possible.For example, Relative density is a dimensionless quantity which is the ratio of two densities. we cannot find the DIMENSION of relative densityThe dimension of fundamental quantities are known and dimensional formulas for other quantities are derived from fundamental units.Example:Finding Dimension of Density:The expression for density is Mass / VolumeMass is a fundamental unit with dimension M.Volume is a cube of length. So, Dimensional Formula for Length L3Dimensional Formula for density M / L3 = ML -3 Explanation:From the definition of acceleration,\(A = \frac{{dv}}{{dt}} = \frac{{{d^2}x}}{{d{t^2}}}\)\(\smallint dv = \smallint A\;dt\)V = A × T\(\frac{x}{T} = A\;T\)⇒ x = A T2To write in the form of Dimensions⇒ x = [F0AT2]