Question

2 trains are approching to each other with speed 72kmph and 90kmph . Distance between trains is 4kms length of each train is 50m . Then find time taken to cross each other is?

Answer 1

Answer:

they cross in 0.025hours

Explanation:

since they are approaching in the same direction add both speeds and then the distance between them is 4kms and 100mtrs so divide 4.1 kms /162

Answer 2

Given :

➳ Speed of train A = 72kmph

➳ Speed of train B = 90kmph

➳ Initial distance b/w them = 4km

➳ Lenth of each train = 50m

To Find :

⟶ Time taken to cross each other.

SoluTion :

✴ Relative velocity of A wrt B :

➨ V(AB) = V(A) - V(B)

➨ V(AB) = 72 - (-90)

➨ V(AB) = 162km/h

[Negative sign of velocity of train B shows motion in opposite direction.]

Conversion :

➛ 1km/h = 5/18m/s

➛ 162km/h = 162 × 5/18 = 45m/s

◕ Total distance covered by each train will be (4km + 50m + 50m) = 4100m

✴ Time taken to cross each other :

⇒ V(AB) = Distance/time

⇒ 45 = 4100/time

⇒ time = 4100/45

⇒ time = 91.11 s = 0.025h