Question

Лодка плыла по течению от одной пристани до другой со скоростью U1=6.0 м\с а обратно со скоростью U2=4.0 м\с. определить среднюю скорость движения лодки на всём пути

Answer 1

Дано
V1=6м/с
V2=4 м/с
S1=S2
Vc-?
Vc=2S1/T
T=t1+t2=S1/6+S1/4=5*S1/12
t1=S1/V1
t2=S1/V2
Vc=2s1*12/5S1=24/5=4.8 м/с

Answer 2

Calculating the Average Speed of the Boat

To calculate the average speed of the boat on the entire journey, we can use the formula for average speed, which is given by:

Average Speed = Total Distance / Total Time

In this case, since the boat travels from one dock to another and then back, the total distance covered in one direction is the same as the total distance covered in the opposite direction. Therefore, we can calculate the average speed using the given speeds for each direction.

Calculating Total Distance

The total distance covered by the boat in one direction is the distance from the first dock to the second dock. Since the boat travels the same distance in the opposite direction, the total distance for the entire journey is twice the distance from one dock to the other.

Calculating Total Time

The total time for the entire journey can be calculated by adding the time taken to travel from the first dock to the second dock and the time taken to travel back from the second dock to the first dock.

Applying the Formula for Average Speed

Once we have the total distance and total time, we can use the formula for average speed to find the average speed of the boat on the entire journey.

Solution

The average speed of the boat on the entire journey can be calculated as follows:

Total Distance = 2 * Distance from one dock to the other

Total Time = (Distance from one dock to the other) / U1 + (Distance from one dock to the other) / U2

Average Speed = Total Distance / Total Time

Let's calculate the average speed using the given speeds U1 = 6.0 m/s and U2 = 4.0 m/s.