Question

Поїзд зі швидкістю 72 км/год рухається на зустріч товарняку,довжина якого 140 м і швидкість 54 км/год.Скільки часу пассажир біля вікна поїзда буде спостерігати товарняк

Answer 1

V1=72км/год.
V2=54 км/год.
L=140м
t-?
1.V=V1+V2
V=72+54=126км/год=35м/с
2.t=L:V
t=140м:35м/с=4с
Вiдповiдь: 4c.

Answer 2

Calculation of Time for Observation

To calculate the time the passenger by the window will observe the oncoming freight train, we can use the concept of relative speed.

The relative speed of the two objects is the difference between their speeds when they are moving towards each other.

The formula to calculate the time of observation is:

Time = Distance / Relative Speed

Given: - Speed of the train = 72 km/h - Length of the freight train = 140 m - Speed of the freight train = 54 km/h

First, let's convert the speed of the train and the freight train from km/h to m/s for consistency.

1 km/h = 5/18 m/s

So, the speed of the train in m/s = 72 * (5/18) m/s = 20 m/s And the speed of the freight train in m/s = 54 * (5/18) m/s = 15 m/s

Now, we can calculate the relative speed of the train and the freight train:

Relative Speed = Speed of the train + Speed of the freight train

Relative Speed = 20 m/s + 15 m/s = 35 m/s

Now, we can calculate the time the passenger by the window will observe the freight train:

Time = Length of the freight train / Relative Speed

Time = 140 m / 35 m/s = 4 seconds

The passenger by the window will observe the freight train for 4 seconds.