Question

4. Вагон, двигаясь равномерно под уклон, 150 м за 15 с. Скатившись с горки, он проходит до полной остановки ещё 450 м за 2 мин. Определите среднюю скорость вагона за всё время движения.

Answer 1

Средняя скорость равна полному пути, деленному на все время.
Полный путь 150м+450м=600м
все время 15с+2 мин=15с+120с=135с
средняя скорость 600м/135c=40/9 м/c=4 4/9 м/c

Answer 2

Calculation of Average Speed

To calculate the average speed of the wagon during its entire journey, we need to consider the two different segments of its motion: when it moves uniformly uphill and when it rolls downhill until it comes to a complete stop.

1. Motion Uphill: The wagon travels a distance of 150 m in 15 s while moving uniformly uphill. To find the average speed during this segment, we can use the formula:

Average Speed = Total Distance / Total Time

Plugging in the values, we have:

Average Speed Uphill = 150 m / 15 s = 10 m/s

2. Motion Downhill: After rolling downhill, the wagon covers an additional distance of 450 m in 2 minutes (120 s) until it comes to a complete stop. Again, we can use the average speed formula:

Average Speed Downhill = Total Distance / Total Time

Plugging in the values, we have:

Average Speed Downhill = 450 m / 120 s = 3.75 m/s

3. Total Average Speed: To find the overall average speed of the wagon for the entire journey, we need to consider the total distance covered and the total time taken. The total distance is the sum of the distances covered uphill and downhill, while the total time is the sum of the times taken uphill and downhill.

Total Distance = Distance Uphill + Distance Downhill = 150 m + 450 m = 600 m

Total Time = Time Uphill + Time Downhill = 15 s + 120 s = 135 s

Now, we can calculate the overall average speed:

Overall Average Speed = Total Distance / Total Time

Plugging in the values, we have:

Overall Average Speed = 600 m / 135 s ≈ 4.44 m/s

Therefore, the average speed of the wagon for the entire duration of its journey is approximately 4.44 m/s.