Physics problem kindly explain how to arrive the answer.

[herbgriffin]

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...
please help...i would like to know how to get the answer..

 

[tiny-tim]

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? ​

 

[herbgriffin]

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]

no, write two equations …

always write equations!​

 

[herbgriffin]

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]

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 traveling in opposite directions,

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