Question

2 trains A and B moving in the same direction.When train A just start to cross B.There velocities are 10 m/s and 10m/s respectively.If their lengths are 30 m and 20 m respectively and acceleration are 3m/s^2 and 2m/s^2 respectively.What is the time taken by the train to cross B

Answer 1

Assuming that Train A crosses B it needs to cover a)Length of Train B
B)Distance Train B covers
So,
Train A covers
S=20+x = ut + 1/2at²
= 10t + 1/2x3xt²
Train B covers
X = ut + 1/2at²
=10t +1/2x2xt²
=10t + t²
Subtracting both equations we get
20 = 3/2t² - t²
20 = 1/2t²
40 = t²
T=2√10