A train moves along the tracks at a constant speed v. A woman on the train throws

Question:

A train moves along the tracks at a constant speed v. A woman on the train throws a ball of mass m straight ahead with a speed v with respect to herself.
(a) What is the kinetic energy gain of the ball as measured by a person on the train?
(b) by a person standing by the railroad track?
(c) How much work is done by the woman throwing he ball and
(d) By the train?