value of g in a planet whose mass is 1/9 of mass of earth and radius is 1/2 of radius of earth
Answers
The classic gravitational attraction equation is:
F=G⋅m1⋅m2d2
What is important here, is not what the actual values are, but how they relate to the final value if they are changed. G, the gravitational constant, and m1, the mass of the object, remain static and will not affect the result. m2 is the mass of the Earth. It is on the top line of the equation so the force changes directly proportional to it.
The radius of the planet affects the result in an inverse square proportion. If the radius increases by a factor of two, the force decreases by a factor of four, if it is trebled, the force decreases by a factor of nine, and so on…… If the radius decreases the opposite occurs, if it halved, the force increases by a factor of four and so on…….
So the new mass reduces the force by a factor of 1/9 but the halving of the radius increases the force by a factor of four.
The new force nF = 9N · 1/9 · 4 = ans.
Now you can easily solve it.