The Brainliest Answer!

This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Gravitational force of attraction on the Moon is given by

F_g = \frac{G\ M_m\ m }{d^2}\\ \\G = universal gravitational constant = 6.67 * 10^{-11} N-m^2/kg^2\\ M_m=mass\ of\ moon\\m=mass\ of\ a\ body\ on\ moon\\d=distance\ of\ mass\ m\ from\ center\ of\ moon\\\\G\ is\ same\ anywhere.\\ \\g_{moon}=\frac{GM_m}{R^2},\ \ R=Radius\ of\ Moon\\

g on the Moon is found to be around 1/6th of g on the Earth.  So it is around 9.81/6 m/sec²
If the net external force on a body is zero, it means the body has an acceleration of 0.  It means the velocity is constant (it can be zero also).  So linear momentum is a constant.over time.   It can be zero also.  

==> Force = rate of change in momentum. = 0.  SO momentum is a constant.

COrrect answer is   c) constant.

3 5 3
so it is correct only what is wrong there?
Force = rate of change in momentum this is what is written in the answer n that's what i m trying to ask whether F=ma ??????
yeah F = ma
force is defined as rate of change of momentum... is equivalent to mass * acceleration = F