An engine absorbs 2000j of heat from a hot reservoir and expels 750j to a cold reservoir during each poerating cycle, (i)what is the efficiency of the engine (ii)How much work is done during the cycle? (iii)What is the power output of the engine if each cycle last for 0.5 seconds?
η={Q(h) –Q(c)}/ Q(h) =
=(2000-750)/2000=0.625 => 62.5%.
W= Q(h) –Q(c) =2000-750=1250 J.
P=W/t=1250/0.5 =2500 W
Expansion joints are used for materials that easily expand and contract depending upon its temperature.How much expansion can take place for a brass pipe 25.8m long that experiences temperature changes of 75.2c
To calculate the efficiency of the engine, you need to use the formula:
Efficiency = (Useful energy output / Total energy input) * 100%
In this case, the useful energy output is the work done, and the total energy input is the heat absorbed.
(i) To find the efficiency of the engine, first calculate the work done:
Work done = Heat absorbed - Heat expelled
= 2000 J - 750 J
= 1250 J
Now, you can calculate the efficiency using the formula mentioned earlier:
Efficiency = (1250 J / 2000 J) * 100%
= 0.625 * 100%
= 62.5%
Therefore, the efficiency of the engine is 62.5%.
(ii) The work done during each cycle is calculated as 1250 J, as we found earlier.
(iii) To find the power output of the engine, you need to use the formula:
Power = Work done / Time
In this case, the work done is 1250 J, and the time for each cycle is 0.5 seconds.
Power = 1250 J / 0.5 s
= 2500 watts
Therefore, the power output of the engine is 2500 watts.