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