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3 years ago

The useful power output of the engine is 2.0 kw. Calculate the rate at which energy is absorbed from the hot reservoir.

Physics

1 answer:

Alika [10]3 years ago

3 0

Answer:

2000 J per second or 2kJ per second.

Explanation:

The definition for power (W) is the rate of energy (J) per unit of time (seconds). In this case the power output is 2kW, or 2000W. This means the energy rate of the engine must be 2000 joules per second, or 2kJ per second.

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Carbon is allowed to diffuse through a steel plate 11 mm thick. The concentrations of carbon at the two faces are 0.88 and 0.41

Serhud [2]

Answer:

The temperature is 2584.5 K

Explanation:

Given:

Activation energy $Q = 80000$ $\frac{J}{mol}$

Preexponential $D= 6.2 \times 10^{-7}$ $\frac{m^{2} }{s}$

Diffusion flux $J = 6.4 \times 10^{-10}$ $\frac{kg}{m^{2} s}$

Thickness of plate $\Delta x = 11 \times 10^{-3}$ m

Concentration of carbon at two faces $\Delta C = (0.88 - 0.41 ) = 0.47$ $\frac{kg}{m^{3} }$

From the formula of temperature in terms of diffusion flux,

$T = (\frac{Q}{R} ) \frac{1}{\ln (\frac{D\Delta C}{J\Delta x} )}$

Where $R =$ 8.314 $\frac{J}{mol.K}$ ( gas constant )

Put the values and find the temperature,

$T = (\frac{80000}{8.314} ) \frac{1}{\ln (\frac{6.2 \times 10^{-7} \times 0.47 }{6.4 \times 10^{-10}\times 11 \times 10^{-3} } )}$

$T = 2584.5$ K

Therefore, the temperature is 2584.5 K

8 0

3 years ago

A 55 kg roller skater is at rest on a flat skating rink, a 198 N horizontal force is needed to set the skater in motion.

Rufina [12.5K]

Answer:

Explanation:

To get the person Moving you have to overcome the static (means not moving) friction coefficient. U(static)

To get the person going at the same speed you have to overcome the kinetic friction coefficient. U(Kinetic)

Force to get him moving is 198 N. Force = ma = U(static)Mg

combining the 2 equations you get 198N = U(static)* 55kg *9.8m/s^2 Solve for U(static)

Same equation to keep him moving except with the dynamic force and the dynamic U

175N= U(kinetic)*55kg*9.8m/s^2 Solve (U dynamic)

8 0

3 years ago

The distance around the block is equal to 3000 feet, how many blocks would you have to run to run a total of a mile?

lesya692 [45]

You would have to run a little less than 2 blocks

7 0

3 years ago

An object has a mass of 5.20g. The mass of the object in kg is

vampirchik [111]

Answer:

0.0520kg

Explanation:

divide by 1000

8 0

3 years ago

Two arrows are shot vertically upward. the second arrow is shot after the first one, but while the first is still on its way up.

Neko [114]

<span>Now that you know the time to reach its maximum height, you have enough information to find out the initial velocity of the second arrow. Here's what you know about it: its final velocity is 0 m/s (at the maximum height), its time to reach that is 2.8 seconds, but wait! it was fired 1.05 seconds later, so take off 1.05 seconds so that its time is 1.75 seconds, and of course gravity is still the same at -9.8 m/s^2. Plug those numbers into the kinematic equation (Vf=Vi+a*t, remember?) for 0=Vi+-9.8*1.75 and solve for Vi to get....... 17.15 m/s</span>

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3 years ago