A train, starting from rest, accelerates along the platform at a uniform rate of 0.6 m/s2. A passenger standing on the platform is 5 m away from the door when the train starts to pull away and heads toward the door at acceleration of 1.2 m/s2. How far away from the door is the passenger after 3 seconds?

Question

A train, starting from rest, accelerates along the platform at a uniform rate of 0.6 m/s2. A passenger standing on the platform is 5 m away from the door when the train starts to pull away and heads toward the door at acceleration of 1.2 m/s2. How far away from the door is the passenger after 3 seconds? 
Help, I answered .4m and it was incorrect.
A) 2.7 m B) 5.4 m C) 0.40 m D) 2.3 m E) 0.90 m

bobpursley · Answer

the train has moved
distance=1/2 .6*3^2=2.7 m
the person has moved...
distance=1/2 *1.2*9=5.4 m OMG, the person has ran onto the tracks, into the train. Lets assume she was smart enough to not do that. I assumed she started at a distance perpendicular to the train. Maybe the author didn't mean that.
Lets try started at behind the door, next to the train.
train went 2.7m, person is now .4 m ahead of where the door was, so the distance is 2.3 m
sloppy wording on the problem, IMO