Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equation of motion of an interstellar Bussard ramjet with radiation and
  mass losses   An interstellar Bussard ramjet is a spaceship using the protons of the
interstellar medium in a fusion engine to produce thrust. In recent papers, it
was shown that the relativistic equation of motion of an ideal ramjet and of a
ramjet with radiation loss are analytical. When a mass loss appears, the limit
speed of the ramjet is more strongly reduced. But, the parametric equations, in
terms of the ramjet's speed, for the position of the ramjet in the inertial
frame of the interstellar medium, the time in this frame, and the proper time
indicated by the clocks on board the spaceship, can still be obtained in an
analytical form. The non-relativistic motion and the motion near the limit
speed are studied.

37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
1
The categories of this paper are: cs