Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The weight of a falling chain, revisited   A vertically hanging chain is released from rest and falls due to gravity on
a scale pan. We discuss the various experimental and theoretical aspects of
this classic problem. Careful time-resolved force measurements allow us to
determine the differences between the idealized and its implementation in the
laboratory problem. We observe that, in spite of the upward force exerted by
the pan on the chain, the free end at the top falls faster than a freely
falling body. Because a real chain exhibits a finite minimum radius of
curvature, the contact at the bottom results in a tensional force which pulls
the falling part downward.

10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con