My miscarriage (@10 wk) started nov11 14/11 u/s: small mass @ cervical os 15/11 passed sac havent bled in >a week is it safe to have sex now?

Yes: Sex isn't clearly implicated in miscarriage at that stage of the pregnancy. Some authorities however think best not to start trying to conceive for 3 months after however.

Ask your treating MD: You need to ask your treating MD, especially if you had a D & C done post miscarriage to be certain that there is no residual material left inside the uterus or an infection is present.