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Vladimir79 [104]
3 years ago
9

What temperature is required to transfer waste heat to the environment for a heat engine to be 100 percent efficient?

Physics
2 answers:
OLEGan [10]3 years ago
6 0
This can be seen as a trick question because heat engines can typically never be 100 percent efficient. This is due to the presence of inefficiencies such as friction and heat loss to the environment. Even the best heat engines can only go up to around 50% efficiency.
nirvana33 [79]3 years ago
6 0

Answer:

An infinite temperature

Explanation:

The efficiency of an engine is defined as:

\eta=1 -\frac{T_C}{T_H}

where

T_H is the temperature at which heat enters the engine

T_C is the temperature of the environment, to which the engine exhausts heat

From the formula, we see that for an engine to be 100% efficient, the fraction

\frac{T_C}{T_H}

must be equal to zero. Since the value of T_C is never zero (the temperature is expressed in Kelvin, and the temperature of the environment can never be exactly 0 K), the only possibility for that to occur is that the temperature at which heat enters the engine (T_H) is infinite, so that this fraction becomes zero and the efficiency becomes 1.

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Which of the following is not a an example of dissipated energy?
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Which of the following is not a an example of dissipated energy?
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When energy is changed from one form to another, ____.

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4 0
3 years ago
In a game of pool, the cue ball moves at a speed of 2 m/s toward the eight ball. When the cue ball hits the eight ball, the cue
agasfer [191]

Answer:

a)  p₀ = 1.2 kg m / s,  b) p_f = 1.2 kg m / s,  c)   θ = 12.36, d)  v_{2f} = 1.278 m/s

Explanation:

a system formed by the two balls, which are isolated and the forces during the collision are internal, therefore the moment is conserved

a) the initial impulse is

        p₀ = m v₁₀ + 0

        p₀ = 0.6 2

        p₀ = 1.2 kg m / s

b) as the system is isolated, the moment is conserved so

       p_f = 1.2 kg m / s

we define a reference system where the x-axis coincides with the initial movement of the cue ball

we write the final moment for each axis

X axis

        p₀ₓ = 1.2 kg m / s

        p_{fx} = m v1f cos 20 + m v2f cos θ

        p₀ = p_f

       1.2 = 0.6 (-0.8) cos 20+ 0.6 v_{2f} cos θ

        1.2482 = v_{2f} cos θ

Y axis  

       p_{oy} = 0

       p_{fy} = m v_{1f} sin 20 + m v_{2f} cos θ

       0 = 0.6 (-0.8) sin 20 + 0.6 v_{2f} sin θ

       0.2736 = v_{2f} sin θ

we write our system of equations

        0.2736 = v_{2f} sin θ

        1.2482 = v_{2f} cos θ

divide to solve

        0.219 = tan θ

         θ = tan⁻¹ 0.21919

         θ = 12.36

let's look for speed

           0.2736 = v_{2f} sin θ

            v_{2f} = 0.2736 / sin 12.36

           v_{2f} = 1.278 m / s

7 0
2 years ago
A man performed 500 j of work moving a couch in his living room
Sergio039 [100]

Incomplete question. Missing part:

"it took him 10 seconds to move the couch. What was his power?"

Answer:

50 W

Explanation:

The power developed is given by:

P=\frac{W}{t}

where

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t is the time taken

In this problem,

W = 500 J

t = 10.0 s

Substituting into the equation, we find

P=\frac{500}{10}=50 W

6 0
3 years ago
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<span>Two of them are "redshift" and "blueshift", which are used to describe an object'smotion toward or away from us in space. Redshift indicates that an object is moving away from us. "Blueshift" is a term that astronomers use to describe an object that is moving toward another object or toward us.</span>
8 0
3 years ago
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