Question

Поднимаясь в гору, лыжник проходит путь, равный 5 км., со средней скоростью 5,4 км/ч. Спускаясь с горы со скоростью 10 м/с., секунду он проходит 2 км. в пути. Определите среднюю скорость движения лыжника на всём пути​

Answer 1

Ответ:

Объяснение:

Дано:

S₁ = 5 км

V₁ = 5,4 км/ч

S₂ = 2 км

V₂ = 10 км/ч

__________

Vcp - ?

1)

Время подъема:

t₁ = S₁ / V₁ = 5 / 5,4 ≈ 0,93 ч

Время спуска:

t₂ = S₂ / V₂ = 2 / 10 = 0,20 с

2)

Полный путь:

S = S₁ + S₂ = 5 + 2 = 7 км

Полное время:

t = t₁ + t₂ =  0,93 + 0,20 = 1,13 ч

Средняя скорость:

Vcp = S / t = 7 / 1,13 ≈ 6,2 км/ч

Answer 2

Calculating the Skier's Average Speed

To calculate the skier's average speed for the entire journey, we need to consider both the uphill and downhill segments separately.

Uphill Segment: - Distance: 5 km - Speed: 5.4 km/h

Using the formula: Average speed = total distance / total time

We can calculate the time taken for the uphill segment: Time = Distance / Speed Time = 5 km / 5.4 km/h Time ≈ 0.9259 hours

Downhill Segment: - Speed: 10 m/s - Distance: 2 km (or 2000 m)

We need to convert the speed from m/s to km/h: 1 m/s = 3.6 km/h So, the speed downhill is: 10 m/s * 3.6 = 36 km/h

Using the formula: Time = Distance / Speed Time = 2 km / 36 km/h Time ≈ 0.0556 hours

Now, we can calculate the total time for the entire journey: Total time = Time uphill + Time downhill Total time ≈ 0.9259 hours + 0.0556 hours Total time ≈ 0.9815 hours

Now, we can calculate the average speed for the entire journey: Average speed = Total distance / Total time Average speed = (5 km + 2 km) / 0.9815 hours Average speed ≈ 7.15 km/h

So, the average speed of the skier for the entire journey is approximately 7.15 km/h.