Two trains are approaching one another from opposite directions on parallel tracks. each train is 150 ft long, but one of the trains is moving at 50 ft/sec, while the other is traveling at only 30 ft/sec. how many seconds elapse from the time the trains first begin to overlap to the time they have completely passed one another?

Time elapsed from the time the trains first begin to overlap to the time they have completely passed one another= 1.875 s

Explanation:

Relative velocity of two trains moving in opposite directions is given by

Vr= V1 + V2

V1= velocity of first train=50 ft/s

V2= Velocity of second train=30 ft/s

so Vr= 50+30= 80 ft/s

distance = d= 150 ft

so the time taken= distance/ relative velocity

t=150/80

t=1.875 s

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