You will need

- Calculator, pen

Instruction

1

Own

The water in the river is moving. So it has its

The speed of boats on the river mark - V via tech., and

**speed**is**the speed**of the boat or another vehicle in still water. Her mark - V own.The water in the river is moving. So it has its

**speed**, called**the speed**u of the flow (V tech.)The speed of boats on the river mark - V via tech., and

**the speed**upstream is V PR. tech.2

Now remember the formulas required to solve problems on the motion:

V PR. tech.= V own. - V tech.

V on tech.= V own. + V tech.

V PR. tech.= V own. - V tech.

V on tech.= V own. + V tech.

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So, based on these formulas, we can draw the following conclusions.

If the boat moves against the river's current, V own. = V PR. tech. + V tech.

If the boat moves with the current, then V own. = V on tech. - V tech.

If the boat moves against the river's current, V own. = V PR. tech. + V tech.

If the boat moves with the current, then V own. = V on tech. - V tech.

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Solve some of the problems on the motion on the river.

Task 1. The speed of the boat against the river's current 12.1 km/h. Find your own

Solution: 12,1 + 2 = 14, 1 (km/h) - private

Task 2. The speed of boats on the river 16.3 km/h,

The decision of 16.3 and 1.9 = 14.4 V (km/h) - private

Task 3. Two boats went at the same time towards each other from two points. The first boat moved up the river, and the second - against the current. They met in three hours. During this time the first boat was 42 km, and the second is 39 km away and Find your own

Solution: 1) 42 / 3 = 14 (km/h) -

2) 39 / 3 = 13 (km/h) -

3) 14 - 2 = 12 (km/h) -

4) 13 + 2 = 15 (km/h) -

Task 1. The speed of the boat against the river's current 12.1 km/h. Find your own

**speed**boats, knowing that**the speed**of river is 2 km/h.Solution: 12,1 + 2 = 14, 1 (km/h) - private

**speed**boat.Task 2. The speed of boats on the river 16.3 km/h,

**the speed**of the river is 1.9 km/HR How many metres would have passed this boat for 1 min., if it was placed in still water?The decision of 16.3 and 1.9 = 14.4 V (km/h) - private

**speed**boat. Translate km/h to m/min: 14.4 V / 0,06 = 240 (m/min). So in 1 minute the boat was 240 m.Task 3. Two boats went at the same time towards each other from two points. The first boat moved up the river, and the second - against the current. They met in three hours. During this time the first boat was 42 km, and the second is 39 km away and Find your own

**speed**of each boat if it is known that**the speed**of river is 2 km/h.Solution: 1) 42 / 3 = 14 (km/h) -

**speed**of traffic on the river the first boat.2) 39 / 3 = 13 (km/h) -

**the speed**of the movement against the current of the river a second boat.3) 14 - 2 = 12 (km/h) -

**speed**of the first boat.4) 13 + 2 = 15 (km/h) -

**speed**of a second boat.Note

Don't forget what units you measure speed.

To convert km/h into m/s you need to divide by 3.6.

To convert m/s to km/h multiply by 3.6.

To convert km/h to m/min divide by 0,06.

To convert m/min into km/h should be multiplied by 0,06.

To convert km/h into m/s you need to divide by 3.6.

To convert m/s to km/h multiply by 3.6.

To convert km/h to m/min divide by 0,06.

To convert m/min into km/h should be multiplied by 0,06.

Useful advice

To solve the problem on the motion of helps pattern.