Misc: what shrinks on some birds to allow them to carry additional food on long flights?

Questions

In Greek mythology, who wanted to remain unmarried until she was defeated in a footrace?

In Greek mythology, who was the father of Electra?

In Irish folklore what is the mischievous elf, often believed to have treasure hoard?

In Joseph Conrad's Lord Jim what ship was abandoned by its crew before it sank?

In physics terminology, what is the tendency of a body in motion to remain in motion?