Question

Расстояние между двумя городами автомобиль проехал за 30 минут. Разгон и торможение вместе длились 8 минут, остальное время автомобиль двигался со скоростью 120км/ч. Определить среднюю скорость (в км/ч) автомобиля. Движение про разгоне и и торможении происходит с одинаковым ускорением (по модулю ).

Answer 1

Ответ;60 км в час.по разгоне

Answer 2

Problem Analysis

To determine the average speed of the car, we need to calculate the total distance traveled and the total time taken. The car traveled for 30 minutes, with 8 minutes spent on acceleration and braking. The remaining time, 22 minutes, the car traveled at a constant speed of 120 km/h. We need to calculate the average speed in km/h.

Solution

To calculate the average speed, we need to find the total distance traveled and the total time taken.

1. Calculate the distance traveled during acceleration and braking: - The time spent on acceleration and braking is 8 minutes. - Since the car is accelerating and braking with the same acceleration, the time spent on each is half of the total time, which is 4 minutes. - The formula to calculate the distance traveled during constant acceleration is: distance = (1/2) * acceleration * time^2. - Since the acceleration is the same for both acceleration and braking, we can calculate the distance for one of them and double it. - The time spent on acceleration and braking is 4 minutes, which is equal to 4/60 hours. - The formula becomes: distance = 2 * (1/2) * acceleration * (4/60)^2.

2. Calculate the distance traveled at a constant speed: - The time spent traveling at a constant speed is 22 minutes. - The formula to calculate the distance traveled at a constant speed is: distance = speed * time. - The time spent traveling at a constant speed is 22 minutes, which is equal to 22/60 hours. - The formula becomes: distance = speed * (22/60).

3. Calculate the total distance traveled: - The total distance traveled is the sum of the distances traveled during acceleration and braking and the distance traveled at a constant speed.

4. Calculate the total time taken: - The total time taken is the sum of the time spent on acceleration and braking and the time spent traveling at a constant speed.

5. Calculate the average speed: - The average speed is the total distance traveled divided by the total time taken.

Let's calculate the average speed step by step.

Calculation

1. Calculate the distance traveled during acceleration and braking: - The acceleration and braking time is 4 minutes. - The acceleration and braking time in hours is 4/60 = 0.067 hours. - The distance traveled during acceleration and braking is: distance = 2 * (1/2) * acceleration * (0.067)^2.

2. Calculate the distance traveled at a constant speed: - The constant speed time is 22 minutes. - The constant speed time in hours is 22/60 = 0.367 hours. - The distance traveled at a constant speed is: distance = speed * (0.367).

3. Calculate the total distance traveled: - The total distance traveled is the sum of the distances traveled during acceleration and braking and the distance traveled at a constant speed.

4. Calculate the total time taken: - The total time taken is the sum of the time spent on acceleration and braking and the time spent traveling at a constant speed.

5. Calculate the average speed: - The average speed is the total distance traveled divided by the total time taken.

Answer

To calculate the average speed of the car, we need to follow the steps outlined above. Unfortunately, we don't have the values for acceleration and speed. Please provide the values for acceleration and speed so that we can calculate the average speed for you.