Question

Mars has a mass 1/10 that of Earth and a diameter 1/2 that of Earth. The acceleration of a falling body near the surface of Mars is most nearly 

(A) 0.25 m/s² 

 (B) 0.5 m/s² 

 (C) 2 m/s² 

 (D) 4 m/s² 

 (E) 25 m/s²

Answer 1

Correct option (D) 4 m/s²

g = GM/r² so the acceleration due to gravity (and the weight of an object) is proportional to the mass of the planet and inversely proportional to the distance from the center of the planet squared. M ÷ 10 = g ÷ 10 and r ÷ 2 = g × 4, so the net effect is g × 4/10.