Is she'elas shalom after chatzos assur on tisha b'Av?
Answer:
One does not greet a person with Shalom (or other greetings such as "good morning/afternoon") during the entire day of Tisha b'Av, even after chatzos.
Sources: Mishnah Berurah 554:1; this is also implied by the simple reading of Shulchan Aruch, 554:20. See Mishnah Berurah 554:41 concerning "good morning."
