Planet Z-34 has a mass equal to 1/3 that of Earth,a radius equal to 1/3 that of Earth,and an axial spin rate 1/2 that of Earth.With g representing,as usual,the acceleration due to gravity on the surface of Earth,the acceleration due to gravity on the surface of Z-34 is
A) g/3.
B) 3g.
C) 6g.
D) g/9.
E) 9g.

Question

Quizplus · Accepted Answer

The acceleration due to gravity (g) on the surface of a planet is directly proportional to the mass of the planet (M) and inversely proportional to the square of the radius (R) of the planet, as given by the formula g = GM/R^2, where G is the gravitational constant. For planet Z-34, with a mass 1/3 that of Earth and a radius 1/3 that of Earth, the acceleration due to gravity on Z-34 would be (1/3)M / (1/3)^2R^2 = (1/3) / (1/9) = 3 times the acceleration due to gravity on Earth, or 3g. The axial spin rate does not affect the calculation of gravitational acceleration.

Planet Z-34 Has a Mass Equal to 1/3 That of Earth,a