physics
posted by teja .
a train goes into a tunnel at 20m/s and emerges from itat 55m/s. the tunnel is 1500m long.assuming constant acceleration the time for which the train moves in tunnel is

a=(V^2Vo^2)/2d
a=(55^220^2)/3000=0.875m/s^2
V = Vo + a*t
t = (VVo)/a = (5520)/0.875 = 40 s.