Question

1.Велосипедист , проехав 3 км со скоростью 12 км/ч, остановился и отдыхал в течение 30 минут. Оставшиеся 5 км он проехал со скоростью 5 км/с. Найти среднюю скорость (в км/ч) велосипедиста на всем пути

Answer 1

Ответ:

Объяснение:

Vcp = S/t = (S1+S2+S3) / (t1+t2+t3) = (3+0+5) / (3/12+0,5+5/5) = 4,57 км/ч

Answer 2

Calculation of Average Speed

To find the average speed of the cyclist on the entire journey, we need to calculate the total time taken and the total distance covered.

Given information: - Distance covered at a speed of 12 km/h: 3 km - Rest time: 30 minutes (0.5 hours) - Distance covered at a speed of 5 km/h: 5 km

Let's calculate the total time taken and the total distance covered:

1. Time taken for the first part of the journey (at a speed of 12 km/h): - Distance: 3 km - Speed: 12 km/h - Time = Distance / Speed = 3 km / 12 km/h = 0.25 hours

2. Time taken for the rest: - Rest time: 30 minutes = 0.5 hours

3. Time taken for the second part of the journey (at a speed of 5 km/h): - Distance: 5 km - Speed: 5 km/h - Time = Distance / Speed = 5 km / 5 km/h = 1 hour

Now, let's calculate the total time taken: - Total time = Time for the first part + Rest time + Time for the second part - Total time = 0.25 hours + 0.5 hours + 1 hour = 1.75 hours

Next, let's calculate the total distance covered: - Total distance = Distance for the first part + Distance for the second part - Total distance = 3 km + 5 km = 8 km

Finally, we can calculate the average speed: - Average speed = Total distance / Total time = 8 km / 1.75 hours ≈ 4.57 km/h.

Therefore, the average speed of the cyclist on the entire journey is approximately 4.57 km/h.