Question

The gravitational field intensity at a point $10,000 \,km$ from the centre of the earth is $4.8 \,N \,kg^{-1}$. The gravitational potential at that point is

• A. $-4.8 \times 10^{-7} \,J \,kg^{-1}$
• B. $-2.4 \times 10^7 \,J \,k^{-1}$
• C. $4.8 \times 10^6 \,J \,kg^{-1}$
• D. $3.6 \times 10^6\, J \,kg^{-1}$

Answer 1

Answer: (A)

Gravitational field intensity, $E = \frac{GM}{R^2}$
Gravitational potential, $V = -\frac{GM}{R}$
$\therefore \frac{V}{E} =-R$
or $V = -ER $
$= - 4.8 \times 10.000\times \times 10^2$
$= -4.8 \times10^7\,J\,kg^{-1}$