Why isn't coulomb's law valid for large conducting objects, even if they are spherically symmetrical?

The Coulomb’s Law is as follows

According to this law, the force between two charged objects can be calculated using the distance between the objects. If the objects are large, then it is not possible to determine the distance, r, between that object and the other object. Because, the edge of the object contain charges as well as the center of the object.

In that case, you need to separate the object into infinitesimal points, apply the formula to those points, then integrate over the large object to find the force between objects.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.