Q 2.15: A famous relation in physics relates ‘moving mass’ to the ‘rest mass’ of a particle in terms of its speed and the speed of light, . (This relation first arose as a consequence of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant c. He writes :
Guess where to put the missing c.
The relation given is
Divide both sides by ; L.H.S becomes which is dimensionless.
Hence, R.H.S must be dimensionless too. (After Dividing by !)
can be dimensionless only when
Therefore, the dimensional equation is