  Based on Suzaku X-ray observations, we study the hot gas around the NGC4839
group of galaxies and the radio relic in the outskirts of the Coma cluster. We
find a gradual decline in the gas temperature from 5 keV around NGC4839 to 3.6
keV at the radio relic, across which there is a further, steeper drop down to
1.5 keV. This drop as well as the observed surface brightness profile are
consistent with a shock with Mach number M = 2.2 pm 0.5 and velocity vs = (1410
pm 110) km s^-1. A lower limit of B > 0.33 mu G is derived on the magnetic
field strength around the relic from upper limits to inverse Compton X-ray
emission. Although this suggests that the non-thermal electrons responsible for
the relic are generated by diffusive shock acceleration (DSA), the relation
between the measured Mach number and the electron spectrum inferred from radio
observations are inconsistent with that expected from the simplest,
test-particle theory of DSA. Nevertheless, DSA is still viable if it is
initiated by the injection of a pre-existing population of non-thermal
electrons. Combined with previous measurements, the temperature profile of Coma
in the southwest direction is shallower outside NGC4839 and also slightly
shallower in the outermost region. The metal abundance around NGC4839 is
confirmed to be higher than in its vicinity, implying a significant peak in the
abundance profile that decreases to 0.2 solar toward the outskirts. We
interpret these facts as due to ram pressure stripping of metal-enriched gas
from NGC4839 as it falls into Coma. The relic shock may result from the
combined interaction of pre-existing intracluster gas, gas associated with NGC
4839, and cooler gas flowing in from the large-scale structure filament in the
southwest.
