Question

Пассажир стоит у окна в пассажирском поезде, движущимся со скоростью 58 км/ч. В течение 4 с. он видит проезжающий мимо товарный поезд, движущийся навстречу со скоростью 50 км/ч.

Answer 1

4c=4/3600=1/900ч
S = (v₁+v₂)t
S=(58км/ч+50км/ч)·(1/900ч)=108км/ч·(1/900ч)=0,12км=120м
Ответ: Длина встречного поезда 120м.

Answer 2

Calculation of the Relative Speed of the Freight Train

To calculate the relative speed of the freight train as observed by the passenger, we need to consider the motion of both trains. The passenger is standing by the window of a passenger train moving at a speed of 58 km/h, while the freight train is moving towards the passenger train at a speed of 50 km/h.

The relative speed of the two trains can be calculated by subtracting the speed of the passenger train from the speed of the freight train. In this case, the relative speed is:

Relative speed = Speed of the freight train - Speed of the passenger train

Relative speed = 50 km/h - 58 km/h

Relative speed = -8 km/h

The negative sign indicates that the two trains are moving in opposite directions.

Calculation of the Time of Observation

The passenger observes the freight train for a duration of 4 seconds. To calculate the distance traveled by the freight train during this time, we can use the formula:

Distance = Speed × Time

Since the relative speed is negative, indicating opposite directions, we take the absolute value of the relative speed to calculate the distance.

Distance = |Relative speed| × Time

Distance = |-8 km/h| × 4 s

Distance = 8 km/h × 4 s = 32 km

Therefore, the freight train travels a distance of 32 kilometers during the 4-second observation period.

Conclusion

In summary, the passenger standing by the window of the passenger train observes a freight train moving towards them at a relative speed of -8 km/h. The passenger observes the freight train for 4 seconds, during which the freight train travels a distance of 32 kilometers.