Question

Автомобиль на горизонтальном участке 10 мин ехал со скоростью 20м/с , затем еще 20 мин со скоростью 10 м/с . какова его средняя скорость на всем пути ?

Answer 1

Vcр=S/t=(V1*t1+V2*t2)/(t1+t2)=(20*600+10*1200)/1800=13,3 м/с

Answer 2

Calculating Average Speed

To calculate the average speed of the car, we can use the formula:

Average Speed = Total Distance / Total Time

First, let's calculate the total distance traveled by the car. The car traveled at a speed of 20 m/s for 10 minutes and then at a speed of 10 m/s for 20 minutes.

Calculating Total Distance

The distance traveled at 20 m/s for 10 minutes is: ``` 20 m/s * (10 minutes * 60 seconds/minute) = 12000 meters ```

The distance traveled at 10 m/s for 20 minutes is: ``` 10 m/s * (20 minutes * 60 seconds/minute) = 12000 meters ```

The total distance traveled is: ``` 12000 meters + 12000 meters = 24000 meters ```

Calculating Total Time

The total time taken is: ``` 10 minutes + 20 minutes = 30 minutes = 1800 seconds ```

Calculating Average Speed

Using the formula: ``` Average Speed = Total Distance / Total Time Average Speed = 24000 meters / 1800 seconds Average Speed ≈ 13.33 m/s ```

Therefore, the average speed of the car on the entire journey is approximately 13.33 m/s.