SOLUTION: Hi,i am not sure if this is the right section, but here is my problem anyway. I am studying mechanics and i have been asked to do this for homework. Telegraph poles, 40m apart

Question 161732: Hi,i am not sure if this is the right section, but here is my problem anyway.
I am studying mechanics and i have been asked to do this for homework.
Telegraph poles, 40m apart stand alongside a straigh railway line. The times taken for a locomotive to pass the two gaps between three consecutive poles are 2.5 seconds and 2.3 seconds, respectively. Assume that the acceleration of the train is constant. Calculate the acceleration of the train and the speed past the first post.
Thanks in advance.
Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
average velocity is (initial velocity + final velocity)/2 __ it is also distance/time

let V1=velocity @ 1st pole, V2=velocity @ 2nd pole, V3=velocity @ 3rd pole

(V1+V2)/2=40/2.5 __ V1+V2=80/2.5=32

(V2+V3)/2=40/2.3 __ V2+V3=80/2.3=34.783

(V1+V3)/2=80/4.8 __ V1+V3=160/4.8=33.333

(V1+V2)+(V2+V3)-(V1+V3)=32+34.783-33.333

2(V2)=33.450 __ V2=16.725

V1=32-16.725 __ V1=15.275 m/s

acceleration=(V2-V1)/2.5 __ a=.58 m/s^2
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