Question

Ширина реки 120 м.Через сколько времени лодка достигнет противоположного берега,если результирующая скорость реки 3м/с а направление перемещения составляет с берегом угол 30 градусов?

Answer 1

120*3 = 360 секунд или 6 минут

Answer 2

Calculation of Time to Reach the Opposite Bank

To calculate the time it takes for a boat to reach the opposite bank of a river, we need to consider the width of the river, the speed of the river, and the angle at which the boat is moving with respect to the bank.

Given: - Width of the river: 120 m - Speed of the river: 3 m/s - Angle of boat's movement with respect to the bank: 30 degrees

To calculate the time, we can break down the boat's velocity into two components: the component parallel to the bank (downstream velocity) and the component perpendicular to the bank (cross-stream velocity).

The downstream velocity can be calculated using the speed of the river: Downstream velocity = Speed of the river = 3 m/s

The cross-stream velocity can be calculated using trigonometry. Since the angle between the boat's movement and the bank is 30 degrees, the cross-stream velocity can be calculated as follows: Cross-stream velocity = Speed of the boat * sin(angle) = Speed of the boat * sin(30 degrees)

To find the speed of the boat, we can use the Pythagorean theorem: Speed of the boat = sqrt((Downstream velocity)^2 + (Cross-stream velocity)^2)

Once we have the speed of the boat, we can calculate the time it takes to cross the river using the formula: Time = Distance / Speed

In this case, the distance is the width of the river, which is 120 m.

Let's calculate the time it takes for the boat to reach the opposite bank.

Calculation:

Downstream velocity = 3 m/s

Cross-stream velocity = Speed of the boat * sin(30 degrees)

Speed of the boat = sqrt((Downstream velocity)^2 + (Cross-stream velocity)^2)

Time = Distance / Speed

Substituting the given values:

Downstream velocity = 3 m/s

Cross-stream velocity = Speed of the boat * sin(30 degrees)

Speed of the boat = sqrt((3 m/s)^2 + (Speed of the boat * sin(30 degrees))^2)

Time = 120 m / Speed of the boat

To solve this equation, we need to find the value of the speed of the boat. Unfortunately, the provided search results do not contain the necessary information to calculate the speed of the boat. Therefore, I am unable to provide a specific answer to your question.

If you have any additional information or if there is anything else I can assist you with, please let me know.