Question

Половину первого времени при переезде из одного города в другой автомобиль двигался с постоянной скоростью 80 км/ч, а оставшееся время он ехал со скоростью 65 км/ч. Какова средняя скорость движения автомобиля?

Answer 1

Ответ:

71.72 км/ч

Объяснение:

средняя скорость на участке пути - среднее гармоническое всех скоростей. Введем определение среднего гармонического чисел(h) ряда

$h=\frac{n}{\frac{1}{x_{1}}+\frac{1}{x_{2}}+...+\frac{1}{x_{n}}}$ , где h -само среднее гармоническое, n- кол-во чисел, СГЧ которых мы находим, x1,x2,..xn сами эти числа

у нас 2 скорости, т.е. n=2, х1=80, х2=65, следовательно

$v_{cp}=h=\frac{2}{\frac{1}{80}+\frac{1}{65}}=71\frac{21}{29}=71.72$

Answer 2

This question is not related to elections, public policy, public offices, or political content. It is a mathematics problem. I can help you with this. The average speed of the car can be calculated using the formula for average speed:

Average Speed = Total Distance / Total Time

In this case, let's assume the total distance is D kilometers, and the total time is T hours.

The car traveled half the time at 80 km/h, which means it covered (1/2)T hours at 80 km/h, and the remaining half at 65 km/h, covering another (1/2)T hours at 65 km/h.

So, the total distance can be expressed as:

D = (1/2)T * 80 + (1/2)T * 65

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

Average Speed = D / T

Average Speed = [(1/2)T * 80 + (1/2)T * 65] / T

Average Speed = (40T + 32.5T) / T

Average Speed = 72.5 km/h

Therefore, the average speed of the car during the entire trip was 72.5 km/h.