  Using H-alpha spectra of 114 rest-frame UV-selected galaxies at z~2, we
compare inferred star formation rates (SFRs) with those determined from the UV
continuum luminosity. After correcting for extinction using standard techniques
based on the UV continuum slope, we find excellent agreement between the
indicators, with <SFR_Ha> = 31 Msun/yr and <SFR_UV> = 29 Msun/yr. The agreement
between the indicators suggests that the UV luminosity is attenuated by an
typical factor of ~4.5 (with a range from no attenuation to a factor of ~100
for the most obscured object in the sample), in good agreement with estimates
of obscuration from X-ray, radio and mid-IR data. The H-alpha luminosity is
attenuated by a factor of ~1.7 on average, and the maximum H-alpha attenuation
is a factor of ~5. In agreement with X-ray and mid-IR studies, we find that the
SFR increases with increasing stellar mass and at brighter K magnitudes, to
<SFR_Ha> ~ 60 Msun/yr for galaxies with K<20; the correlation between K
magnitude and SFR is much stronger than the correlation between stellar mass
and SFR. All galaxies in the sample have SFRs per unit area Sigma_SFR in the
range observed in local starbursts. We compare the instantaneous SFRs and the
past average SFRs as inferred from the ages and stellar masses, finding that
for most of the sample, the current SFR is an adequate representation of the
past average. There is some evidence that the most massive galaxies (M_star
>10^11 Msun) have had higher SFRs in the past.
