Misc: What is the element symbol for Manganese?

Questions

in norse mythology, who is the chief of the valkyries?

in one of donald horne's novels, as what was australia dubbed?

in one of donald horne's novels, who was the lucky country?

in order for a deck of cards to be mixed up enough to play with properly, at least how many times should it be shuffled?

in physics and engineering, the property of a body that causes it to return to its original position or motion as a result of the action of the so-called restoring forces, or torques, once the body has been disturbed from a condition of equilibrium?