The problem of water flow in elementary school, the problem of flowing water is learned in the first

Set drifting for t hours.

Then there is 3t+(14+3)*(8-t)=94 to get t=3

Note: The actual speed of the boat is the speed of the water plus the speed of the boat in still water, that is, 14km h, and the actual speed of the boat is the same as the speed of the water when drifting.

If the ship does not break down, it can travel in 8 hours (14 + 3) * 8 = 136 km.

Now 136-94 = 42 km less.

Rafting is 14 kilometers less than normal travel.

So drifting for 42 14 = 3 hours.

Note: The actual speed of the boat is the speed of the water plus the speed of the boat in still water, that is, 14km h, and the actual speed of the boat is the same as the speed of the water when drifting.

That is: the speed at which the boat travels normally = the speed of the ship + the speed of the water.

Rafting speed = water speed.

Set: Drifted for x hours.

From the meaning of the question, 3x+(14+3)*(8-x)=94 solved x=3 answers, and drifted for 3 hours.

Assuming that the vessel does not break down within 8 hours.

8 hours of driving :(14+3)* 8 = 136 km.

More lines than actual: 136-94 = 42 km.

42 14 = 3 hours ......The time when a cargo ship drifts in the river.

The cargo ship drifted in the river for 3 hours.

Set rafting for x hours.

3x+(8-x)(14+3)=94

x = 3 cargo ships drifted in the river for 3 hours.

Fifth grade. The problem of running water is also called the problem of flowing water, which refers to the fact that when the ship is sailing in the river, in addition to its own forward speed, it is also pushed or reversed by the flowing water, and the speed, time and distance traveled by the ship are calculated under this situation.

Downstream speed = boat speed + water current speed.

Countercurrent speed = boat speed The speed of the current.

Hydrostatic speed (boat speed) = (speed of the river + speed against the water) 2.

Water velocity = (velocity against the water) 2.

Example: A steamer travels 28 kilometers per hour from A to B, and then sails against the current back to A. The water travels 2 hours longer than the downstream, and the known water speed is 4 kilometers per hour. Find out how many kilometers apart A and B are between them.

Analysis: In this question, you must first know the speed of the water and the time it takes to go along the water, or the speed of the water and the time to go against the water. It is not difficult to calculate the speed of the reverse water, but the time taken to go against the water, the time taken to go against the water is not known, only that the time taken by the water is 2 hours less than the reverse water, and if you grasp this point, you can calculate the time taken by the water from A to B, so that you can calculate the distance between A and B.

If a passenger ship sails 120 kilometers per hour in the Yangtze River and the water speed is 2 kilometers per hour, how many hours does the passenger ship need to sail?

Let's take a look, the conditions tell us that "the speed of the passenger ship in the still water is 22 kilometers per hour" and "the water speed is 2 kilometers per hour", according to the number of relationships: the speed of the water = the speed of the still water + the speed of the water, you can first find the speed of the passenger ship, and then divide the distance of the water by the speed of the water is equal to the time of the water sailing.

120 (22+2)=120 24=5 (hours).

The water addition speed is equal to the water reduction rate, and the original speed difference is 1 + 1 = 2 water speeds, and the return trip continues to pull 1 + 1 = 2 water speeds.

Total 2+2=4

2 4 = kilometers each.

It took only half an hour to meet on the way back, so the water speed was 1 2=1 km h.

Because A is going down the river and B is going against the current and the first time they meet, the two ships A and B have traveled the same distance, and the time of meeting is t

Therefore, (v A + v water) * t = (v B - v water) * t because when the two ships meet for the second time, ship A travels 2 kilometers less than ship B and the time between the first encounter and the second encounter is 1 hour apart.

So (v B + v water) * (1-t) - (v A - v water) * (1-t) = 2 (v B + v water) * (1-t) + (v A - v water) * (1-t) = (v A + v water) * t + (v B - v water) * t

According to the third formula, t=

Then according to the first two equations, and bring in t=, the solution is: v water = 1 km hour.

Set drifting for t hours.

Then there is 3t+(14+3)*(8-t)=94

Solution t=3 Description: Driving in the water.

The actual speed of the boat is the speed of the water plus the speed of the boat in still water, i.e. 14km h, the actual speed of the boat when drifting.

and the same speed of water.

Downstream velocity = hydrostatic velocity + water velocity

Countercurrent velocity = hydrostatic velocity – water velocity velocity.

Hydrostatic velocity = (downstream velocity + countercurrent velocity) 2

Water velocity = (downstream velocity - countercurrent velocity) 2

Boat speed in the downstream water = boat speed in still water + water speed.

Boat speed in reverse water = boat speed in still water - water speed.

Flowing water boating problems.

The relationship between the three quantities of distance, speed and time in the travel problem: distance = speed When the time boat sails in the river, in addition to its own forward speed, it is also pushed or reversed by the flowing water, in this case, the calculation of the sailing speed, time and distance traveled by the ship is called the flowing water sailing problem. The running water problem is one of the travel problems, so the relationship between the three quantities (speed, time, and distance) in the travel problem will be used again and again.

In addition, there is the following basic formula for the problem of flowing water boating:

Downstream speed = boat speed Water speed.

Speed against the water = speed of the boat The speed of the water.

Velocity + Velocity against the Current) 2 = Boat speed.

Velocity against the water) 2 = velocity of the water.

v Shun = v static + v water.

v inverse = v static - v water.

Do you want a title? Or the answer, the answer is to write the question.

Downstream speed = boat speed in still water + water speed.

Velocity against the water = velocity at still water – water velocity.

Boat speed + flowing water speed = downstream speed.

Boat speed - flow speed = speed against the current.

Do you want a formula? Or is it the answer? It's better to be clear

The speed of the water flow is 10 2 5 km, the time of the water is 25 10 hours, the time of the reverse water is 6 hours, the time of the reverse water is 25 kilometers, and the speed of still water is 25 5 30 kilometers per hour.

1. The pool is full in 6 hours, and the water is released in 8 hours.

2. There are two inlet pipes in a pool, and a single pipe can fill the whole pool in 1 2 hours, and a single pipe B can fill the whole pool in 1 3 hours. If the two tubes A and B are opened at the same time, how many hours can the empty pool be filled?

3. A water inlet pipe in the pool, a water outlet pipe can be opened at the same time to put the water in the full pool in 60 minutes, if the water inlet pipe is opened separately, and it takes 90 minutes to fill the pool, ask how much time to open the outlet pipe alone, you can put the water in the full pool.

4. The inlet pipe is full in 20 minutes, and the outlet pipe is emptied in 40 minutes. Q: The inlet pipe and the outlet pipe are opened together, and how long does it take to put it full?

5. There is a pool with a water inlet pipe that is constantly inflowing, there are 24 identical water pipes to pump water in 6 hours, if you use 21 water pipes to pump water it takes 8 hours, if you use 16 water pipes, how many hours does it take?

Chinese, Mathematics, English, Science... What kind、

Set the speed of the boat to be x and the speed of the current to y

1) From A to B, the speed of the boat is X-Y, and the time is half an hour, and the kettle has been following the wave from A for half an hour, and the distance is.

2) From B to the kettle, when chasing the kettle, because it is all downstream, it can be seen as in still water, the kettle does not move, and the boat goes back to get the kettle at the speed of x, and the distance between the two is the distance between the two when the boat reaches place B in step (1) =

So the time is half an hour.

These are all additional ideas. You don't need to write when you do the question, just write your sentence.

From the time the kettle falls into the water, the boat speed = the speed of the boat in the still water - the speed of the water.

Kettle drifting speed = water speed.

The speed of the boat and the kettle is the speed of the boat.

In half an hour, the distance between the boat and the kettle is the speed of the boat

The boat turned around, and the kettle was a matter of pursuit.

The boat is also along the water, speed = still water speed + water speed.

Kettle drifting speed or water speed.

The difference between the speed of the boat and the kettle is the speed of the boat in still water + the speed of the water - the speed of the water = the speed of the still water boat and the pursuit time is: the speed of the still water boat The speed of the still water = hours.

Half an hour, the distance between the boat and the kettle is actually half an hour (the speed of the boat, the kettle, and the speed of the boat in still water).

When chasing water bottles, the difference in speed between them is also when the boat is in still water.

It should have taken half an hour for the boat to get from ground B to catch up with the kettle.

The boat catches up with the kettle, and then it takes another 10 minutes to return to place A, the speed is the speed of the boat - the speed of the water to the boat catches up with the kettle, the kettle has been gone for an hour, the speed of the water is the speed of the boat - the speed of the water = 6 times the speed of the water.

Boat speed = 7 times the speed of water.

Boat speed + water speed = 8 times water speed = 4 (boat speed - water speed) 3 small boats go against the water, the speed is boat speed - water speed, from a to b, it takes half an hour to travel from b to a, the speed is boat speed + water speed.

Time required = 30 3 4 = minutes.

Because the kettle goes down the water, there is a speed of water;

And the boat goes against the current, minus one speed of water;

The velocity of the two approaches should be the addition of the two velocities, and the two water velocities cancel out.

The key to a turnover problem like this is to grasp the implicit conditions, which can be solved relatively easily.

Do you understand? If you don't understand, you can ask.

The speed of the water is fixed, and both the kettle and the boat have bonuses, so after everyone subtracts the speed of the water together, can it be understood that the kettle is stationary?

It's like, you're on a very long train with the kettle, and the train is moving. You and the kettle are in the train, and your kettle falls on the ground in the train, and then you walk forward in the train for half an hour, can you walk half an hour backward and meet the kettle? In fact, it has nothing to do with whether the train is moving or not, a truth.

Well, velocity vectors, so use vectors and calculations.

Let the speed of the water flow be x, and then the speed of the laughter and waiting is 34+x when the water is noisy, and the speed of the reverse water is 34-x

Then s Shunshui = (34+x)*8 s Reverse Shui = (34-x)*9 S Shunshui = S Ascend against the Current.

So (34+x)*8=(34-x)*9 gives x=2, so that's 2km h.

The distance along the river divided by time minus the speed of the water is equal to the speed of the voyage, and if you want to go 320 kilometers against the water, it is 320 divided by 30 kilometers per hour.