I had hysterectomy & novasure endometrial ablation done 5 weeks ago, my doctor has not been specific as to when is safe to have sex. is it safe now?

Clarify: It is unlikely that you had a hysterectomy and endometrial ablation done at the same time. Do you mean hysteroscopy? If so, it's probably safe.

U mean hysteroscopy: I recommend no intercourse for two weeks, but your physican may want you to wait longer, so you should follow his/her instructions. There is no need to wait six weeks. Remember, there are alternatives to intercourse ;).