Question

Пароход, двигаясь против течения со скоростью 15 км/ч, проходит расстояние между двумя пристанями за 4 ч. За какое время он пройдёт то же расстояние по течению, если скорость парохода по течению равна 5,5 м/с? Ответ: время равно ч. (Результат округляй до десятых!)

Answer 1

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Answer 2

Problem Analysis

We are given that a steamboat is traveling against the current with a speed of 15 km/h and it takes 4 hours to cover a certain distance between two piers. We need to find out how long it will take for the steamboat to cover the same distance with the current flowing at a speed of 5.5 m/s.

Solution

To solve this problem, we can use the concept of relative velocity. The speed of the steamboat relative to the water is the difference between its actual speed and the speed of the current.

Let's calculate the speed of the steamboat relative to the water: - Speed of the steamboat = 15 km/h - Speed of the current = 5.5 m/s

To convert the speed of the steamboat from km/h to m/s, we need to multiply it by 1000/3600 (since 1 km/h = 1000 m/3600 s).

The speed of the steamboat relative to the water is then: - Speed of the steamboat relative to the water = (15 km/h) * (1000 m/3600 s) - (5.5 m/s) = 13.89 m/s - 5.5 m/s = 8.39 m/s

Now, we can calculate the time it will take for the steamboat to cover the same distance with the current: - Distance = Speed * Time - Time = Distance / Speed

Let's assume the distance between the piers is D. The time it will take for the steamboat to cover the same distance with the current is: - Time = D / (8.39 m/s)

To find the value of D, we can use the given information that it takes 4 hours to cover the distance between the piers against the current. We know that: - Time = 4 hours = 4 * 3600 seconds

Therefore, we can calculate the distance D as follows: - D = Speed * Time = (15 km/h) * (1000 m/3600 s) * (4 * 3600 s) = 15 km

So, the distance between the piers is 15 km.

Now, we can calculate the time it will take for the steamboat to cover the same distance with the current: - Time = D / (8.39 m/s) = (15 km) / (8.39 m/s) = 1791.63 seconds

Rounding the time to the nearest tenth, we get: - Time = 1791.6 seconds

Therefore, the steamboat will take approximately 1791.6 seconds to cover the same distance with the current flowing at a speed of 5.5 m/s.

Answer: The steamboat will take approximately 1791.6 seconds to cover the same distance with the current flowing at a speed of 5.5 m/s.