# Physics problem kindly explain how to arrive the answer.

## Homework Statement

Two trains start at the same time from stations A and B (6km apart ) respectively in opposite tracks. train A accelerates uniformly at the rate of 0.5 meter per second square until it reaches a speed of 54 kmph, while train B accelerates uniformly at the rate of 0.6 meter per second square until it reaches a speed of 72 kmph and then travels at this speed. Determine when and where both will cross each other

## Homework Equations

i don't know what equation to use........

## The Attempt at a Solution

i tried equating there distance but it will just complicate the equation....

tiny-tim
Homework Helper
hi herbgriffin! start by writing out the two equations for the positions of the two trains at any time t (put the origin, x = 0, at A) …

what do you get? i will get train a will be 225 m at t=30s while train b is 333.33 m at t=33.33s. I don't know if this is right........

tiny-tim
Homework Helper
no, write two equations

always write equations!

x=15+[(1/2) (0.5)t^2] train A
x= 20+[(1/2) (0.6) t^2] train B
please correct me if i am wrong i am really confused

tiny-tim
Homework Helper
hi herbgriffin! (try using the X2 icon just above the Reply box )
x=15+[(1/2) (0.5)t^2] train A
x= 20+[(1/2) (0.6) t^2] train B
please correct me if i am wrong i am really confused

your 1/2 (0.5)t2 and 1/2 (0.6)t2 parts are correct,

but i don't understand where your 15 and 20 come from also you haven't shown them travelling in opposite directions,

and you haven't dealt with the steady motion after each trains reaches its cruising speed