Question

Поезд длиной 800 метров проехал мимо дежурного по станции за 40 секунд ,а тоннель за 1,5 минут . найдите длину трннеля.

Answer 1

800/40=20 м/сек
1,5мин=90 сек
20*90=1800 метров

Answer 2

Calculating the Length of the Tunnel

To find the length of the tunnel, we can use the information provided about the time it took for the train to pass the station and the tunnel.

Given: - Length of the train = 800 meters - Time taken to pass the station = 40 seconds - Time taken to pass the tunnel = 1.5 minutes

First, let's convert the time taken to pass the tunnel from minutes to seconds: 1.5 minutes = 1.5 * 60 = 90 seconds

Now, we can use the concept of relative speed to calculate the length of the tunnel.

Using Relative Speed to Calculate the Length of the Tunnel

When the train passes through the tunnel, it covers its own length plus the length of the tunnel in the same time it takes to cover just its own length when passing the station.

The relative speed of the train with respect to the tunnel is the same as the speed of the train when passing the station.

Let's denote: - Length of the tunnel as L (in meters) - Speed of the train as S (in meters per second)

The equation for the time taken to pass the station is: Time = Distance / Speed So, for passing the station: 800 meters = 40 seconds * S

The equation for the time taken to pass the tunnel is: Time = (Length of train + Length of tunnel) / Speed So, for passing the tunnel: (800 meters + L) = 90 seconds * S

We can solve these two equations to find the length of the tunnel L.

Calculating the Length of the Tunnel

By solving the above equations, we can find the length of the tunnel. Let's proceed with the calculations.

800 = 40S 800 + L = 90S

Now, we can solve these equations to find the value of L.

By solving these equations, we find: L = 2200 meters

The length of the tunnel is 2200 meters.