Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Royal Observatory of Belgium Gravitational balance   An astatized symmetrical vertical pendulum is monitoring torque {\Gamma}(M)
resulting of gravitational attractions exerted by two external masses M moving
up down. Local gravity field g produce the main pendulum restoring torque
combined with a very weak variable torque {\Gamma}(c) induced by rotation of
watch needles fixed to the pendulum. Transfer of fundamental units to calibrate
the {\Gamma}(c) torques is obtained by a reference torque {\Gamma}({\mu})
resulting of precise displacements of a well known mass {\mu}. We permanently
monitored ratio between the gravitational effect {\Gamma}(M) and calibrated
{\Gamma}(c) to determine G. Position of the pendulum is measured with a
capacitive bridge. Bias voltages sent to two electrodes set-up at the bottom of
the pendulum allows to feedback pendulum with a controlled electrostatic
torque. We discuss potential interest of our prototype to design a multi
pendulum system to check systematic effects for different geometries and
various kinds of materials.

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The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol