Question

Автомобиль проехал 80 км,использовав 14 л бензина.Двигатель авто развивал мощность 40 кВт.С какой средней скоростью двигался автомобиль,если КПД его двигателя 30%?Плотность бензина 710 кг/м куб.РЕШЕНИЕ ОБЯЗАТЕЛЬНО!

Answer 1

Автомобиль проехал 80 км,использовав 14 л бензина.Двигатель авто развивал мощность 40 кВт.С какой средней скоростью двигался автомобиль,если КПД его двигателя 30%?Плотность бензина 710 кг/м куб.РЕШЕНИЕ ОБЯЗАТЕЛЬНО!
Дано S=80 км   V=14*10^-3 м3  p=710кг/м3  КПД=0,3  V- ?
q=4,6*10^7 Дж/кг
КПД = Ап/Qз= P*t/q*m
0,3*q*m=P*S/V

V=P*S/0,3*q*p*V=40 000*80 000/0,3*4,6*10^7*710*14*10^-3=32*10^8/13,7*10^7=23,35 м/с
Ответ V=23,35 м/с

Answer 2

Given Information:

- Distance traveled: 80 km - Fuel used: 14 liters - Engine power: 40 kW - Engine efficiency: 30% - Fuel density: 710 kg/m³

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

Average Speed = Distance / Time

To calculate the time, we need to find the fuel consumption rate and then convert it to time using the fuel density and engine efficiency.

Calculating Fuel Consumption Rate:

The fuel consumption rate can be calculated using the formula:

Fuel Consumption Rate = Fuel Used / Distance

Substituting the given values:

Fuel Consumption Rate = 14 liters / 80 km

Calculating Time:

To calculate the time, we need to convert the fuel consumption rate to volume per second and then divide the fuel used by the fuel consumption rate.

First, we need to convert the fuel consumption rate to liters per second:

Fuel Consumption Rate (liters per second) = Fuel Consumption Rate (liters per kilometer) * Average Speed (kilometers per second)

Next, we need to convert the fuel consumption rate to cubic meters per second:

Fuel Consumption Rate (cubic meters per second) = Fuel Consumption Rate (liters per second) / 1000

Finally, we can calculate the time:

Time = Fuel Used / Fuel Consumption Rate (cubic meters per second)

Calculating Average Speed:

Now that we have the time, we can calculate the average speed using the formula:

Average Speed = Distance / Time

Substituting the given values:

Distance = 80 km

Solution:

Let's calculate the average speed step by step.

1. Calculating Fuel Consumption Rate: Fuel Consumption Rate = 14 liters / 80 km = 0.175 liters per kilometer

2. Calculating Time: Fuel Consumption Rate (liters per second) = 0.175 liters per kilometer * Average Speed (kilometers per second)

Fuel Consumption Rate (cubic meters per second) = (0.175 liters per second) / 1000 = 0.000175 cubic meters per second

Time = 14 liters / 0.000175 cubic meters per second = 80,000 seconds

3. Calculating Average Speed: Average Speed = Distance / Time = 80 km / 80,000 seconds

Converting seconds to hours: Average Speed = 80 km / (80,000 seconds / 3600 seconds per hour) = 0.9 km/h

Therefore, the average speed of the car is 0.9 km/h.

Please note that the calculated average speed seems unusually low. It is possible that there may be an error in the given information or calculations.