Question

Поднимаясь в гору, лыжник проходит путь, равный 3 км, со средней скоростью 5,4 км/ч. спускаясь с горы со скоростью 10 м/с. он проходит 1 км пути. определите среднюю скорость движение лыжника на всем пути.

Answer 1

Почему-то мне кажется 7,7 =)
5,4+10=15,4/2=7,7

Answer 2

Calculating the Skier's Average Speed

To calculate the skier's average speed for the entire journey, we'll need to consider both the uphill and downhill segments of the trip.

Uphill Segment: - Distance: 3 km - Speed: 5.4 km/h

Downhill Segment: - Distance: 1 km - Speed: 10 m/s

Calculating Average Speed for the Uphill Segment

To find the time taken for the uphill segment, we can use the formula: \[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]

Using this formula, the time taken for the uphill segment is: \[ \text{Time} = \frac{3 \, \text{km}}{5.4 \, \text{km/h}} = 0.5556 \, \text{hours} \]

Calculating Average Speed for the Downhill Segment

To find the time taken for the downhill segment, we can use the formula: \[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]

Converting the downhill speed to km/h: \[ 10 \, \text{m/s} = 10 \times 3.6 = 36 \, \text{km/h} \]

Using this speed, the time taken for the downhill segment is: \[ \text{Time} = \frac{1 \, \text{km}}{36 \, \text{km/h}} = 0.0278 \, \text{hours} \]

Calculating the Total Time and Average Speed

The total time for the entire journey is the sum of the times for the uphill and downhill segments: \[ \text{Total Time} = 0.5556 \, \text{hours} + 0.0278 \, \text{hours} = 0.5834 \, \text{hours} \]

To find the average speed for the entire journey, we can use the formula: \[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \]

The total distance for the entire journey is 4 km. Therefore, the average speed for the entire journey is: \[ \text{Average Speed} = \frac{4 \, \text{km}}{0.5834 \, \text{hours}} \approx 6.857 \, \text{km/h} \]

So, the average speed of the skier for the entire journey is approximately 6.857 km/h.