M1 s=ut+1/2at^2

Where do they get the 2 from? How does u=2?

Q: A train moves along a straight track with constant acceleration. 3 telegraph poles are set at equal intervals beside the track at points A, B and C, where AB=50m and BC=50m. The front of the train passes A with speed 22.5ms^{-1}, and 2s later passes B

Find the acceleration of the train.

I get u=0, v=22.5, s=50, t=2 and a is what we're finding

so we use this equation, s=ut+1/2at^2

sub in. 50=0(2)+1/2a4

50=2a, a=22.5

Whereas the answer has 50=2(22.5)+1/2a4

Where do they get the 2 from? How does u=2?

Q: A train moves along a straight track with constant acceleration. 3 telegraph poles are set at equal intervals beside the track at points A, B and C, where AB=50m and BC=50m. The front of the train passes A with speed 22.5ms^{-1}, and 2s later passes B

Find the acceleration of the train.

I get u=0, v=22.5, s=50, t=2 and a is what we're finding

so we use this equation, s=ut+1/2at^2

sub in. 50=0(2)+1/2a4

50=2a, a=22.5

Whereas the answer has 50=2(22.5)+1/2a4

Where do they get the 2 from? How does u=2?

You revising Mechanics for the exam on friday? Me too.

Basically u=22.5 s=50 t=2 v=0

if you sub all this in you end up with acceleration = 2.5 ms-2.
Where have you got this question from?

v=0?

First of all its wrong and second of all why bring V into the equation? You don't need it....the train is moving with constant acceleration....

Sorry...my bad not reading questions right, or what i type

This Question is from Edexcel M1 June 06 exam, Q3.

Slightly wierd 4 answers within the space of two mintues.

edited

Sorry?