Question

The mass of a planet is $\frac{1}{10}$th that of the earth and its diameter is half that of the earth. The acceleration due to gravity on that planet is :

• A. 19.6 m s–2
• B. 9.8 m s–2
• C. 4.6 m s–2
• D. 3.92 m s–2

Answer 1

Answer: (D)

3.92 m s–2

Answer 2

Acceleration due to gravity is given by:

$g = \frac{GM}{R^2}$.

Here, $M_p = \frac{M}{10}$ and $R_p = \frac{R}{2}$.

Substituting:

$g_p = \frac{G(M/10)}{(R/2)^2} = \frac{g}{5} = \frac{9.8}{2.5} = 3.92 \, m/s^2$.