Question

Потяг проїхав 0,4 км зі швидкістю 20 м/с, потім ще 20 с рухався зі швидкістю 36 км/год. Яка середня швидкість потяга за весь час руху?​

Answer 1

Ответ:

v ср = всё расстояние / всё время

S = 400 + (20*36/3.6) = 200 м + 400м = 600 м

t = 20 + 400 / 20 = 40 +20 = 60 с

v = S/t = 600 / 60 = 10 м/с

Answer 2

Calculation of Average Speed

To calculate the average speed of the train, we need to find the total distance traveled and the total time taken.

The train traveled 0.4 km with a speed of 20 m/s, which can be converted to 72 km/h. Then, it traveled for an additional 20 seconds with a speed of 36 km/h.

Let's calculate the total distance and total time taken:

1. Distance traveled at 20 m/s: - Distance = Speed × Time - Distance = 20 m/s × 20 s = 400 m = 0.4 km

2. Distance traveled at 36 km/h: - Distance = Speed × Time - Distance = 36 km/h × (20 s / 3600 s) = 0.2 km

Now, let's calculate the total distance and total time taken:

- Total distance = 0.4 km + 0.2 km = 0.6 km - Total time = 20 s + 20 s = 40 s

Finally, we can calculate the average speed:

- Average speed = Total distance / Total time - Average speed = 0.6 km / 40 s = 0.015 km/s = 54 km/h

Therefore, the average speed of the train for the entire duration of the journey is 54 km/h.