  Measuring the effect of gravity on antimatter is a longstanding problem in
physics that has significant implications for our understanding of the
fundamental nature of the universe. Here, we present a technique to measure the
gravitational mass of atoms, motivated by a recent measurement of antimatter
atoms in CERN [1]. We demonstrate the results on ultra-cold atoms by measuring
the surviving fraction of atoms gradually released from a quadrupole magnetic
trap, which is tilted due to gravitational potential. We compare our
measurements with a Monte Carlo simulation to extract the value of the
gravitational constant. The difference between the literature value for g, the
local acceleration due to gravity, and the measured value is $(-1.9 \pm
12^{stat} \pm 5^{syst}) \times 10^{- 4} g$. We demonstrate the importance of
various design parameters in the experiment setup, and estimate their
contribution to the achievable accuracy in future experiments. Our method
demonstrates simplicity, precision, and reliability, paving the way for future
precision studies of the gravitational force on antimatter. It also enables a
precise calibration of atom traps based on the known gravitational attraction
of normal matter to Earth.
