Question

why does the core of a star collapse after fusion has stopped? the strong nuclear force binds extra material in the core of the star, increasing the density of the core and leads to the collapse of the star. the formation of a black hole pulls additional material into the core, resulting in the collapse of the core. the pressure from the core causes the star to collapse. the gravitational attraction of the material in the star is large enough to overcome the outward radiation pressure from the core.

Explanation:

When fusion in a star's core stops, there is no longer sufficient outward - radiation pressure to counteract the inward gravitational pull of the star's mass. Gravity then causes the core to collapse. The strong nuclear force is not the cause of this collapse, black hole formation is a result of the collapse in some cases, not the cause, and it's not the pressure from the core causing the star to collapse but rather the lack of outward pressure to oppose gravity.

Answer:

The gravitational attraction of the material in the star is large enough to overcome the outward radiation pressure from the core.