Escape velocity of a body from earth is \\( 11.2 \\, \\text{km/s} \\). If the radius of a planet be one-third the radius of earth and mass be one-sixth that of earth, the escape velocity from the planet is:
\\( 4.2 \\, \\text{km/s} \\)
\\( 8.4 \\, \\text{km/s} \\)
\\( 11.2 \\, \\text{km/s} \\)
\\( 7.9 \\, \\text{km/s} \\)