Take Earth’s mass as and its radius as

PHYSICS · Subjective · CBSE · Physics · Gravitation · Gravitation

Problem

Take Earth’s mass as

M_{\oplus}=5.97\times10^{24}\,\text{kg}

and its radius as

R_{\oplus}=6.37\times10^{6}\,\text{m}

. The universal gravitational constant is

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

. (i) Calculate the magnitude of Earth’s gravitational field intensity at the surface. (ii) At what altitude

h

above the Earth’s surface will the gravitational field intensity become one-fourth of the surface value obtained in part (i)? Express

h

both in metres and in kilometres. (iii) How does the result of part (ii) compare with the Earth–Moon distance (

3.84\times10^{8}\,\text{m}

)? Comment briefly.