1edit [3] : : my goodness '!!'
3.7 Two trains A and B of length 400 m each are moving on two parallel tracks with a uniform speed of 72 km h–1 in the same direction, with A ahead of B. The driver of B decides to overtake A and accelerates by 1 m s–2. If after 50 s, the guard of B just brushes past the driver of A, what was the original distance between them ? if we use this formula.. xBA(t) = xB (t) – xA (t)= [ xB (0) – xA (0) ] + (vB – vA) t. what shall we put for the value of vB ? n please explain the answer.
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3 Answers
1my goodness ??
y use all those formulae??
tgis is simple question...
jus relative distance = x (say) = 1/2 a t2
put a and t, x=.... something...
62Paromita... This formula that you have used is for the case when V(a) and V(b) are constant.
(In cases where this formula is applicable, the acceleration of the trains is zero....)
We are in the case when there is acceleration. So this formula that you are trying to use will be invalid...
You have to "look" for a formula where the acceleration is given.....
Good Luck :)