Approximate the Earth as a sphere of mass and radius

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Approximate the Earth as a sphere of mass

6.0\times10^{24}\,\text{kg}

and radius

6.4\times10^{6}\,\text{m}

. Using

G=6.67\times10^{-11}\,\text{N}\,\text{m}^2\,\text{kg}^{-2}

, determine the escape speed from Earth’s surface. (a)

15.8\,\text{km}\!/\!\text{s}

(b)

7.9\,\text{km}\!/\!\text{s}

(c)

11.2\,\text{km}\!/\!\text{s}

(d)

22.4\,\text{km}\!/\!\text{s}