A famous relation in Physics relates moving mass m to the rest mass `m_0` of a particle in terms of its speed `upsilon` and the sped of light c. (This relaiton first arose as a consequence of special theory of relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant c. He writes `m = (m_0)/((1 - upsilon^2)^(1//2)`Guess where to put the missing c?

Explanation

According to the principle of homogeneity,
The dimensions on left side of an equation = The dimensions on the right side of an equation.
Hence, to make the dimensions on both the sides of equation equal, the denominator must be dimensionless, instead of `(1-u^2)^(1/2)` factor at the denominator, there should be `u^(2)"/"c^(2)`.
`m=(m_0)/((1-(u^2)/(c^2))^(1/2))`.