Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reflection off Surfaces of Revolution: a Teachers' primer to the
  Introduction of the Cross-section Concept   The differential cross-section for the reflection of light beams off rigid
bodies obtained by the rotation of a generic derivable convex function is
calculated. The calculation is developed using elementary notions of calculus
and is therefore suitable for calculus oriented introductory undergraduate
university physics courses. Three particular cases are presented as examples of
the general procedure and of the physical properties and considerations about
cross-sections they allow to discuss in class.

35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex