We present new vsini measurements for 235 low-mass stars in the Pleiades. The
differential rotational broadening has been resolved for all the stars in our
sample. These results, combined with previously published measurements, provide
a complete and unbiased rotation data set for stars in the mass range from 0.6
to 1.2 Msol. Applying a numerical inversion technique on the vsini
distributions, we derive the distributions of velocities for low-mass Pleiades
members. Comparison of the rotational distributions of low-mass members between
IC 2602/2391 and the Pleiades suggests that G dwarfs behave like solid-bodies
and follow Skumanich's law during this time span. However, comparison between
Pleiades and older clusters (M34 and Hyades) indicates that the braking of slow
rotators on the early main sequence is weaker than predicted by an asymptotical
Skumanich's law. This strongly supports the view that angular momentum tapped
in the radiative core of slow rotators on the zero age main sequence (ZAMS)
resurfaces into the convective envelope between Pleiades and Hyades age. For
the G-dwarfs, we derive a characteristic coupling time scale between the core
and the envelope of about 100--200Myr. The relationship between rotation and
coronal activity in the Pleiades is in agreement with previous observations in
other clusters and field stars. We show that the Rossby diagram provides an
excellent description of the X-ray activity for all stars in the mass domain
studied. The Pleiades data for slow and moderate rotators fills the gap between
the X-ray--rotation correlation found for slow rotators and the X-ray
``saturation plateau'' observed for young fast rotators.Comment: 17 pages, 9 figures. Accepted for publication in Astronomy and
Astrophysics Main Journa