Question

Show that the value of g = 9.8 m/s given

Answer 1

as f = ma

as there  is acceleration due to gravity so,

f = mg

we know that ,

f = GMm/$r^{2}$

mg =  GMm/$r^{2}$ (small m get cut off )

g = GM/$r^{2}$

as we know,

G = 6.67 * $10^{-11}$

mass of earth = 6 * $10^{24}$ kg

and radius of earth = 6.4  * $10^{6}$ m

so,

g = 6.67 * $10^{-11}$ * 6 * $10^{24}$ kg / 6.4  *  $10^{6}$ m

which is equal to 9.8

therefore value of g = 9.8

---------hence shown