Answer
The block will tip first.
Work Step by Step
We know that the block will slide when the frictional force is less than the gravitational force pulling the object down the ramp. Thus, we find:
$mgsin\theta=F_n\mu \\ mgsin\theta = mgcos\theta \mu \\ \theta = tan^{-1}(.63)=32.2^{\circ}$
We know the block will tip when the net torque is greater than zero. Thus, we find:
$\frac{h}{4}mgcos\theta=\frac{h}{2}mgsin\theta \\ \theta = tan^{-1}(.5)=26.56^{\circ}$
The block will tip first.
