Question

Да поезда, длина которых одинакова, движутся навстречу друг другу. скорость первого поезда 54 км/ч, а второго 36 км/ч. второй поезд проехал мимо пассажира, сидящего в первом поезде, за 14 с. какова длина каждого поезда?

Answer 1

Относительно пассажира (так как он сам движется в 1-м поезде навстречу 2-му поезду) второй поезд движется со скоростью v=72+54=126 (км/час)=126000 м/час= 35 м/сек. Поэтому длина 2-го поезда L=14•35=490 (м).

Answer 2

Problem Analysis

We are given two trains moving towards each other. The speed of the first train is 54 km/h, and the speed of the second train is 36 km/h. The second train passes a passenger sitting in the first train in 14 seconds. We need to find the length of each train.

Solution

Let's assume the length of the first train is x and the length of the second train is y.

To find the length of each train, we can use the formula:

Distance = Speed × Time

For the first train, the distance covered is the sum of the lengths of both trains, which is x + y. The speed is 54 km/h, and the time is 14 seconds.

For the second train, the distance covered is the length of the second train, which is y. The speed is 36 km/h, and the time is 14 seconds.

Using the formula, we can set up the following equations:

x + y = (54 km/h) × (14 s)

y = (36 km/h) × (14 s)

Now, let's solve these equations to find the values of x and y.

Calculation

Using the given speeds and time:

x + y = (54 km/h) × (14 s)

y = (36 km/h) × (14 s)

Simplifying the equations:

x + y = 756 km

y = 504 km

Substituting the value of y in the first equation:

x + 504 km = 756 km

Solving for x:

x = 252 km

Answer

The length of the first train is 252 km, and the length of the second train is 504 km.

Please note that the units used in the calculations are kilometers, as the speeds and lengths are given in kilometers per hour.