In the old west, a marshal riding on a train traveling 35.0 m/s sees a duel between two men standing on the earth 55.0 m apart parallel to the train. the marshal's instruments indicate that in his reference frame the two men fired simultaneously. (a) which of the two men, the first one the train passes (a) or the second one (b) should be arrested for firing the first shot? that is, in the gunfighter's frame of reference, who fired first? (b) how much earlier did he fire? (c) who was struck first?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".