Question

The mass of the planet Mars is 6 × ${10}^{23}$ kg and radius is 4.3 × ${10}^6$ m. Calculate the weight of a man on Mars whose weight on earth is 600 N. (Given g on earth = 10 $\frac{m}{{sec}^2}$)

Answer 1

Weight of the man earth, W = mg

or 600 = m * 10 or m = 60 kg

So the mass of the man is 60 kg which will remain the same everywhere.

Now acceleration due to gravity on Mars,

$g_m$ = $\frac{GMm}{{R^2}_m}$

Here, $M_m$ = 6 * ${10}^{23}$ kg ; $R_m$ = 4.3 * ${10}^6$ m

∴ $g_m$ = $\frac{6.67\ast {10}^{-11}\ast 6\ast {10}^{23}}{{(4.3\ast {10}^6)}^2}$ = 2.17 $\frac{m}{{sec}^2}$

Now, weight of the man on Mars will be

$W_m$ = m * $g_m$ = 60 * 2.17 = 130.2 N