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Snezhnost [94]
3 years ago
12

A heat engine has a cold reservoir of 250°C and a hot reservoir of 715°C. What is the efficiency of the engine?

Physics
2 answers:
Margarita [4]3 years ago
6 0
If the heat engine is a perfect carnot cycle engine, then
efficiency = (T2-T1)/T2  
where T1=temperature of cold reservoir ( ° K) = 250+273.15 = 523.15
           T2=temperature of hot reservoir ( ° K)  = 715+273.15 = 988.15

Therefore
efficiency = (T2-T1)/T2 = (988.15-523.15)/988.15 = 0.4706 = 47% 

Note: this is the theoretical maximum efficiency of a perfect heat engine.  Real-life engines do not achieve this value.
Illusion [34]3 years ago
5 0

The answer is A. 65.0% for plato users, i got 100% on the test  :)

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The concept that large masses warp the shape of spacetime and thus change the path of an object moving through that spacetime ap
mrs_skeptik [129]

Answer: Newton's law of gravity theory disagrees with Einstein's theory. The last one were named Theory of General Relativity and was discovered and proposed by the physicist Einstein in the year of 1915.

Explanation: Until the beginning of 20 century, the physics were ruled by Isaac Newton's ideas. He believed that the gravity was a force caused by the objects mass on the space, made them to be draw towards each other. Newton thought that the greater the mass of the object, the more intense was its attraction, which would justify the planet's moovements around the sun and how the gravity between them maintain the planets on solar orbit. Concluding, he believed gravity was a immediate force of action, regardless of the distance of the bodies.

Contrary to Newton's law of gravity, in 1915, the physicist Einstein created the Theory of General Relativity, wich discovered that gravity was, in fact, the deformation caused by the attraction of massive celestial bodies. This deformation, related to the Sun, for example, creates a curvature on the space-time and this curvature are followed by the other planets.

So, we can conclude that Newton's law of gravity disagree's with the Theory of General Relativity, once the first believes that light force of attraction are transmitted instantly and, as Einstein already prooved, the gravity influency propagates in the speed of light.

4 0
3 years ago
A mass of 0.1 kg of helium fills a 0.2 m3 rigid tank at 350 kPa. The vessel is heated until the pressure is 700 kPa. Calculate t
QveST [7]

Explanation:

(a)   First, we will calculate the number of moles as follows.

       No. of moles = \frac{\text{mass}}{\text{molar mass}}

Molar mass of helium is 4 g/mol and mass is given as 0.1 kg or 100 g (as 1 kg = 1000 g).

Putting the given values into the above formula as follows.

       No. of moles = \frac{\text{mass}}{\text{molar mass}}

                             = \frac{\text{100 g}}{4 g/mol}  

                             = 25 mol

According to the ideal gas equation,

                           PV = nRT

or,       (P_{2} - P_{1})V = nR (T_{2} - T_{1})

          (6.90 atm - 3.45 atm) \times 200 L = 25 \times 0.0821 L atm/mol K \Delta T

          \Delta T = 336.17 K

Hence, temperature change will be 336.17 K.

(b)   The total amount of heat required for this process will be calculated as follows.

                   q = mC \Delta T

                      = 100 g \times 5.193 J/g K \times 336.17 K

                      = 174573.081 J/K

or,                  = 174.57 kJ/K        (as 1 kJ = 1000 J)

Therefore, the amount of total heat required is 174.57 kJ/K.

3 0
3 years ago
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Sedbober [7]

Answer:

mass

Explanation:

3 0
3 years ago
Read 2 more answers
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