Question

1/3 часть пути человек ехал на велосипеде со скоростью 15км/ч а остаток пути шёл со скоростью 5км/ч Какова его средняя скорость на протяжении пути

Answer 1

Пусть S - общий путь.

1)
Время на первом участке:
t₁ = (1/3)* S/V₁ = S / (3*V₁) = S / (3*15) = S / 45

2)
Время на втором участке:
t₂ = (2/3)* S/V₂ = 2*S / (3*V₂) = 2*S / (3*5) = 2*S / 15

3)
Общее время:
t = t₁+t₂ = S/45 + 2*S/15 = 7*S/45

4)
Средняя скорость:
Vcp = S / t = 45*S / (7*S) = 45/7 ≈ 6,4 м/с

Answer 2

Calculation of Average Speed

To calculate the average speed of a person who traveled one-third of the distance on a bicycle at a speed of 15 km/h and the remaining distance on foot at a speed of 5 km/h, we can use the formula for average speed:

Average Speed = Total Distance / Total Time

Let's assume the total distance traveled is D km. Since the person traveled one-third of the distance on a bicycle, the distance traveled on the bicycle is (1/3)D km. The remaining distance traveled on foot is (2/3)D km.

To find the total time, we need to calculate the time taken for each part of the journey.

The time taken for the bicycle part of the journey can be calculated using the formula:

Time = Distance / Speed

For the bicycle part, the time taken is (1/3)D / 15 hours.

The time taken for the walking part of the journey can be calculated using the same formula:

Time = Distance / Speed

For the walking part, the time taken is (2/3)D / 5 hours.

Now, we can calculate the total time taken by adding the times for the bicycle and walking parts:

Total Time = (1/3)D / 15 + (2/3)D / 5

Finally, we can calculate the average speed using the formula:

Average Speed = Total Distance / Total Time

Substituting the values, we get:

Average Speed = D / [(1/3)D / 15 + (2/3)D / 5]

Simplifying the expression, we get:

Average Speed = 15 / [(1/3) + (2/3) * 3]

Calculating the expression, we find:

Average Speed = 15 / (1 + 2) = 15 / 3 = 5 km/h

Therefore, the average speed of the person throughout the journey is 5 km/h.