  We consider different types of external color sources that move through a
strongly-coupled thermal N=4 super-Yang-Mills plasma, and calculate, via the
AdS/CFT correspondence, the dissipative force (or equivalently, the rate of
energy loss) they experience. A bound state of k quarks in the totally
antisymmetric representation is found to feel a force with a nontrivial
k-dependence. Our result for k=1 (or k=N-1) agrees at large N with the one
obtained recently by Herzog et al. and Gubser, but contains in addition an
infinite series of 1/N corrections. The baryon (k=N) is seen to experience no
drag. Finally, a heavy gluon is found to be subject to a force which at large N
is twice as large as the one experienced by a heavy quark, in accordance with
gauge theory expectations.
