Physics, 16.07.2019 23:00 mahalabear8120

Imagine a carnot engine has a hot reservoir of 680 k and a cold reservoir of 220 k. what is the efficiency of the engine? 58.3% 75.9% 62.3% 72.1% 67.6%

Answers: 1

Show answers

Answers

N = 1 - (QC/QH)

n = efficiency

QC = Cold Reservoir = 220 K
QH = Hot Reservoir = 680 K

$n = 1 - (220 \div 680) (\div 10)\\ n = 1 - (22 \div 68) (\div 2) \\ n = 1 - (11 \div 34) \\ n = (34 - 11) \div 34 \\ n = 23 \div 34 \\ n = 0.676... \times 100\\ n = 67.6$

The engine's efficiency is 67.6% .

Answer from: peytontanner

the other person's right, it's E. 67.6% for plato users :)

Answer from: Quest

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

Answer from: Quest

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

$f\alpha \frac{dp}{dt}$

⇒ $f= k \frac{dp}{dt}$

here k is the proportionality constant whose value is 1.

$f=\frac{dp}{dt}$

$f= \frac{d[mv]}{dt}$

$f= m\frac{dv}{dt} +v\frac{dm}{dt}$

$f=ma+v\frac{dm}{dt}$ [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

Another question on Physics

Physics, 22.06.2019 04:00

Determine the maximum r-value of the polar equation r =3+3 cos 0

Answers: 3

Answer

Physics, 22.06.2019 09:30

Why are graphs useful when interpreting data

Answers: 2

Answer

Physics, 22.06.2019 10:20

What determines the amount of inertia an object has

Answers: 2

Answer

Physics, 22.06.2019 15:30

Two pans of a balance are 24.1 cm apart. the fulcrum of the balance has been shifted 1.33 cm away from the center by a dishonest shopkeeper. by what percentage is the true weight of the goods being marked up by the shopkeeper? assume the balance has negligible mass. answer in units of %.

Answers: 1

Answer

You know the right answer?

Imagine a carnot engine has a hot reservoir of 680 k and a cold reservoir of 220 k. what is the effi...

Questions