Questions on Personal Jurisdiction in Federal Court

Here are some questions on PJ in federal court.

1) A brings suit in federal court in Virginia against B, a German domiciliary residing in Germany, for a battery that the German committed against him in Delaware. The German has no other contacts with the United States. Is personal jurisdiction over B constitutionally allowed? Is it allowed under Fed. R. Civ. P. 4(k)?

2) Same question as 1, except A is suing B under federal law.

3) Assume that Yasser Arafat is sued under a federal antiterrorism act allowing for American victims of foreign terrorism to sue for damages. The action is brought in federal court in New York. Does the federal court have the power to take the case under 4(k)?

4) Why does Fed. R. Civ. P. 4(k)(2) exist? Why does it apply only to actions brought under federal law, not state law?