Question

Calculate the escape velocity (in ${\text{km s}}^{-1}$) of Neptune. The mass of Neptune $\approx {10}^{26}\text{kg}$, radius of Neptune, $\approx 24,170\text{km}$

• A. 23.5

Answer 1

The correct option is A 23.5
Given:
The mass of Neptune, $\text{M}\approx {10}^{26}\text{kg}$
The radius of Neptune, $\text{R}\approx 24,170\text{km}$

The escape velocity of Neptune, ${\text{v}}_{\text{esc}}=\sqrt{\frac{\text{2GM}}{\text{R}}}$
$=\sqrt{\frac{2\times 6.67\times {10}^{-11}\times {10}^{26}}{24,170\times {10}^3}}$
$=23,493{\text{m s}}^{-1}$
$\approx 23.5{\text{km s}}^{-1}$