Question

A train crosses a tunnel in 25 seconds. At the entry of the tunnel, its velocity is 54 km/hr and at the exit of the tunnel, the velocity is 72 km/hr. Then the length of the tunnel is

Answer 1

Answer:

437.5 m

Explanation:

t= 25 s

u= 54 km/h =15 m/s

v= 72km/h = 20 m/s

now,

a = v- u/t [ from v= u + at]

then by putting the value of all variables

we get a= 0.2 m per s square

now we have to use the formula

s = ut + 1/2 at*2

s = 15 × 25 + 1/2 ×0.2× 25 ×25

by solving this we get 437.5 m