## College Physics (4th Edition)

$p = 4.9~mc$
We can find the magnitude of the momentum: $E^2 = p^2c^2+m^2c^4$ $(5.0~mc^2)^2 = p^2c^2+m^2c^4$ $25~m^2c^4 = p^2c^2+m^2c^4$ $p^2c^2 = 24~m^2c^4$ $p^2 = 24~m^2c^2$ $p = \sqrt{24}~mc$ $p = 4.9~mc$