Question

Скорость течения реки 4 м/с. Моторная лодка идёт по течению со скоростью 15 км/ч (относительно воды). С какой скоростью она будит двигаться простив течения (относительно берега) если скорость относительно воды не изменится ?

Answer 1

15км/ч= 15000/3600 (м/с)=25/6 (м/с)
Скорость лодки против течения 25/6-4=1/6 (м/с)

Answer 2

Calculation of the Boat's Speed Relative to the Shore

To calculate the speed of the motorboat relative to the shore, we need to consider the speed of the current and the speed of the boat relative to the water.

Given: - Speed of the river current: 4 m/s - Speed of the motorboat relative to the water: 15 km/h

To find the speed of the motorboat relative to the shore, we can use the following formula:

Speed of the motorboat relative to the shore = Speed of the motorboat relative to the water + Speed of the river current

Let's convert the speed of the motorboat relative to the water from km/h to m/s:

Speed of the motorboat relative to the water = 15 km/h * (1000 m/1 km) * (1 h/3600 s) = 4.17 m/s

Now we can calculate the speed of the motorboat relative to the shore:

Speed of the motorboat relative to the shore = 4.17 m/s + 4 m/s = 8.17 m/s

Therefore, the motorboat will move at a speed of 8.17 m/s relative to the shore when the speed of the motorboat relative to the water remains unchanged.