A large boulder has been perched on the side of a mountain for many years. What change would cause it to suddenly roll down the mountain?

he weight vector approaches the point within the mass, the equilibrium becomes unstable

any change in the conditions of the environment can cause the rock to slide

Explanation:

In general, a rock in a mountain is in stable equilibrium with the help of the force of gravity that causes its weight to be within the center of mass, that is, the weight vector is first and then it is electing the center of mass.

When for some reason the weight vector approaches the point within the mass, the equilibrium becomes unstable, and any change in the conditions of the environment can cause the rock to slide, for example a rain that reduces the friction force.

It may happen that the weight vector is after the center of the hubs, in this case there is an unstable balance and the stone is held in place by the force of friction with the environment that surrounds it, if this friction decreases the rock will slide .

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.