Question

При сгорании топлива в тепловом двигателе за 30 минут выделилась энергия 10.8 мегаджоуль .определите мощность двигателя,если его кпл 20%?

Answer 1

кпд=А(пол)/А(зат)*100%

А(пол)=Р*t

A(зат)- энергия выделившаяся при сгорании

P*t*100%=кпд*А(зат)

p-мощность

p=кпд*А(зат)/100%*t

подставляем циферки и считаем: р=12*10^2=1200Вт

ответ 1,2кВт

Answer 2

Calculation of Engine Power

To determine the power of the engine, we need to use the formula:

Power = Energy / Time

Given that the energy released during the combustion of fuel in the thermal engine is 10.8 megajoules and the time taken is 30 minutes, we can calculate the power of the engine.

Converting the time from minutes to seconds:

Time = 30 minutes * 60 seconds/minute = 1800 seconds

Now, we can calculate the power using the formula:

Power = 10.8 megajoules / 1800 seconds

Calculating the power:

Power = 0.006 megajoules/second

However, we also need to consider the engine's efficiency, which is given as 20% (0.2). The efficiency is defined as the ratio of useful work output to the energy input.

To calculate the actual power output of the engine, we need to multiply the calculated power by the efficiency:

Actual Power = Power * Efficiency

Calculating the actual power:

Actual Power = 0.006 megajoules/second * 0.2

Actual Power = 0.0012 megajoules/second

Therefore, the power of the engine, considering an efficiency of 20%, is 0.0012 megajoules/second.

Please note that the calculation assumes a constant power output throughout the 30-minute period. In reality, the power output of an engine may vary depending on various factors.