Gather secondary information to predict the value of acceleration due to gravity on other planets.
  • The gravitational force on an object is determined by the planet's mass and "radius".
    • Subsequently the gravitational acceleration ($g$) would also depend on those factors.
  • To find the value of $g$ on other planets we would $F = mg$ and $F = \frac{GMm}{r^2}$:
\begin{align} F_g = \frac{GMm}{r^2} \end{align}

But as $F = mg$

\begin{align} mg = \frac{GMm}{r^2} \end{align}

Now remove $m$ from both sides:

\begin{align} g = \frac{GM}{r^2} \end{align}


  • $g$ is the acceleration due to gravity ($ms^{-2}$)
  • $G$ is Newton's Universal gravitational Constant. ($6.67 x 10^{-11} Nm^2kg^{-2}$)
  • $M$ is the mass of the planet. ($kg$)
  • $r$ is the radius of the planet. ($m$)