Calculate the momentum of electron moving with ` 1//3` 3rd velocity of light .

Explanation

Mass of the moving electron `(m') = (m_("rest"))/(sqrt(1 - ((v)/(c))^(2))`
Putting `v = (c)/(3)`
`m' = (m)/(sqrt(1 ((c)/(3c))^(2))) = (m)/(sqrt(1 - ((1)/(3))^(2))) = (3m)/(sqrt8)`
Momentum `= m'v = (3m)/(sqrt8) xx (c)/(3) =(mc)/(sqrt8) = ((9.11 xx 10^(-31)kg) (3 xx 10^(10) ms^(-1)))/(2.828) = 9.66 xx 10^(-21) kg m s^(-1)`