Let's see. The heat output of radioactive materials should be, assuming the planet has an earthlike composition, proportional to volume(treat that as g^3). The surface area through which that heat must pass is proportional g^2. So the heat throughput per unit area would be proportional to g^(3/2). This is the energy driving mountainbuilding.
Erosion rates should be proportional to boundary shear stress.
tau0=rho*g*R*s, where rho is the density of water(essentially a constant), g is gravity, R is the hydraulic radius(lets ignore that for now, I can't see why it would vary with gravity), and s is the slope over which the water is falling.
Thus, erosion is proportional to gravity.
Given all that, mountain heights should be an equilibrium between driving energy and erosion. So I figure mountain height would vary roughly as the square root of gravity.
1.25g > mountains 1.12 times as high. 1.50g > mountains 1.22 times as high.
Hmm... Not the result I was expecting.
_________________ My little attempt at a blog dedicated to worldbuilding .
