Rankers Physics
Topic: Gravitation
Subtopic: Gravitational Potential

At what height from the surface of earth the gravitation potential and the value of $g$ are $-5.4 \times 10^{7} \text{ J kg}^{-1}$ and $6.0 \text{ ms}^{-2}$ respectively. Take the radius of earth as $6400 \text{ km}$:

(2016 - I)

$2600 \text{ km}$
$1600 \text{ km}$
$1400 \text{ km}$
$2000 \text{ km}$

Solution:

Potential $V = -\frac{GM}{r} = -5.4 \times 10^{7}$ and $g = \frac{GM}{r^{2}} = 6.0$. Dividing $|V|$ by $g$ gives $r = 9000 \text{ km}$. Height $h = r - R = 9000 - 6400 = 2600 \text{ km}$.

Leave a Reply

Your email address will not be published. Required fields are marked *