Question

Автомобиль ехал из города М в город по прямой дороге, половину пути со скорость 40 км/ч , а вторую половину со скоростью 60 км/ч. Найдите его среднию скорость за всё время путешествия

Answer 1

средняя скорость=все расстояние/все время в пути

весь путь=S

время в пути :  t1 = S/2     и   t2=S/2      t1+t2

                                v1               v2

 v=   2*v1*v2    

        v1+ v2

 

 

v=2*40*60  =4800/100=48(км/ч)-средняя скорость за всё время путешествия

     40+60

Answer 2

Calculation of Average Speed

To find the average speed of the car during the entire journey, we need to calculate the total distance traveled and the total time taken.

Let's assume the total distance traveled is D and the total time taken is T.

The car traveled the first half of the distance with a speed of 40 km/h and the second half with a speed of 60 km/h.

Since the distance traveled in each half is the same, we can say that the first half of the distance is D/2 and the second half is also D/2.

To calculate the total time taken, we can divide the distance traveled in each half by the respective speeds:

- Time taken for the first half of the distance: (D/2) / 40 - Time taken for the second half of the distance: (D/2) / 60

The total time taken is the sum of these two times:

T = (D/2) / 40 + (D/2) / 60

Now, we can calculate the average speed by dividing the total distance by the total time:

Average Speed = Total Distance / Total Time

Substituting the values, we get:

Average Speed = D / [(D/2) / 40 + (D/2) / 60]

Let's calculate the average speed using this formula.

Calculation:

Since we don't have the specific value of the distance traveled, we cannot calculate the exact average speed. However, we can provide a general formula to calculate the average speed based on the distance.

Let's assume the distance traveled is D km.

The total time taken is:

T = (D/2) / 40 + (D/2) / 60

Simplifying the equation:

T = D/80 + D/120

Combining the terms:

T = (3D + 2D) / 240

T = 5D / 240

Now, we can calculate the average speed:

Average Speed = Total Distance / Total Time

Average Speed = D / (5D / 240)

Simplifying the equation:

Average Speed = 240 / 5

Average Speed = 48 km/h

Therefore, the average speed of the car for the entire journey is 48 km/h.

Please note that this calculation assumes a constant speed throughout each half of the journey and does not take into account any other factors that may affect the actual average speed.