Question

A train of length 450 m travels at the speed of 90 km/h. How long does it take to cross a lamp post and a tunnel 50 m long?​

Answer 1

Step-by-step explanation:

Velocity    v=30 km/h=30×185=8.3 m/s

Time taken to cross    t=36 s

Let the length of bridge be L.

Distance covered by train to cross  d=50+L

So,     L+50=36×8.3

⟹ L≈250 m

Answer 2

Answer:

Given:

Length of the train = 450m

Speed of the train = 50 m/s

Time taken to cross the man = 10 seconds

Formula used:

Speed(S) = Distance(D)/Time(T)

Calculation:

Let the speed of the man be x m/s

Speed at which train crossed the man = 450/10 m/s

⇒ 45m/s

In the same direction, the speed subtracts

⇒ (50 – x) m/s = 45 m/s

⇒ x = 5 m/s

∴ The speed of the man is 5 m/s.