Question

Find the mass of Planet X, given that its radius is 3.39e6m and that the acceleration due to gravity on its surface is 3.73m/s2

Answer 1

6.313 × 10²³ kg

From the Newtons;

F = GMm/r²

Where G = 6.67×10⁻¹¹ m²/kgs²

F = ma

ma = GMm/r²

Dividing by m on both sides

a = GM/r²

M = ar²/G

= 3.73 × (3.39×10⁶)²/ 6.67×10⁻¹¹

= 4.211×10⁻¹³/ 6.67×10⁻¹¹

= 6.313 × 10²³ kg