  We study global inertial-modes with the purpose of unraveling the role they
play in the tidal dissipation process of Jupiter. For spheres of uniformly
rotating, neutrally buoyant fluid, we show that the partial differential
equation governing inertial-modes can be separated into two ordinary
differential equations when the density is constant, or when the density has a
power-law dependence on radius. For more general density dependencies, we show
that one can obtain an approximate solution to the inertial-modes that is
accurate to the second order in wave-vector. Frequencies of inertial-modes are
limited to $\omega < 2 \Omega$ ($\Omega$ is the rotation rate), with modes
propagating closer to the rotation axis having higher frequencies. An
inertial-mode propagates throughout much of the sphere with a relatively
constant wavelength, and a wave amplitude that scales with density as
$1/\sqrt{\rho}$. It is reflected near the surface at a depth that depends on
latitude, with the depth being much shallower near the special latitudes
$\theta = \cos^{-1} \pm \omega/2\Omega$. Around this region, this mode has the
highest wave amplitude as well as the sharpest spatial gradient (the
``singularity belt''), thereby incurring the strongest turbulent dissipation.
Inertial-modes naturally cause small Eulerian density perturbations, so they
are only weakly coupled to the tidal potential. In a companion paper, we
attempt to apply these results to the problem of tidal dissipation in Jupiter.
