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konstantin123 [22]

2 years ago

9

Determine the specific heat of a certain metal if a 450 gram sample of it loses 34 500 Joules of heat as its temperature starts

at 150 oC and drops to 53 oC.

1 answer:

slamgirl [31]2 years ago

6 0

Answer:

c = 0.4356 J/gK

Explanation:

Given the following data;

Mass = 450 grams

Initial temperature, T1 = 150°C

Final temperature, T2 = 53°C

Quantity of heat = 34500 Joules

To find the specific heat capacity of the metal;

Heat capacity is given by the formula;

$Q = mcdt$

Where;

Q represents the heat capacity or quantity of heat.

m represents the mass of an object.

c represents the specific heat capacity of water.

dt represents the change in temperature.

dt = T2 - T1

dt = 53 - 150

dt = -97°C

Converting the temperature in Celsius to Kelvin, we have;

dt = 273 + (-97) = 176 Kelvin

Making c the subject of formula, we have;

$c = \frac {Q}{mdt}$

Substituting into the equation, we have;

$c = \frac {34500}{450*176}$

$c = \frac {34500}{79200}$

c = 0.4356 J/gK

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Which of the following is a consequence of the special theory of relativity?

aleksandr82 [10.1K]

Answer:

D.

Explanation:

Specifically, Special Relativity showed us that space and time are not independent of one another but can be mixed into each other and therefore must be considered as the same object, which we shall denote as space-time. The consequences of space/time mixing are: time dilation. and length contraction.

3 0

2 years ago

Steam enters an adiabatic turbine steadily at 7 MPa, 5008C, and 45 m/s, and leaves at 100 kPa and 75 m/s. If the power output of

marusya05 [52]

Answer:

a) $\dot m = 6.878\,\frac{kg}{s}$ , b) $T = 104.3^{\textdegree}C$ , c) $\dot S_{gen} = 11.8\,\frac{kW}{K}$

Explanation:

a) The turbine is modelled by means of the First Principle of Thermodynamics. Changes in kinetic and potential energy are negligible.

$-\dot W_{out} + \dot m \cdot (h_{in}-h_{out}) = 0$

The mass flow rate is:

$\dot m = \frac{\dot W_{out}}{h_{in}-h_{out}}$

According to property water tables, specific enthalpies and entropies are:

State 1 - Superheated steam

$P = 7000\,kPa$

$T = 500^{\textdegree}C$

$h = 3411.4\,\frac{kJ}{kg}$

$s = 6.8000\,\frac{kJ}{kg\cdot K}$

State 2s - Liquid-Vapor Mixture

$P = 100\,kPa$

$h = 2467.32\,\frac{kJ}{kg}$

$s = 6.8000\,\frac{kJ}{kg\cdot K}$

$x = 0.908$

The isentropic efficiency is given by the following expression:

$\eta_{s} = \frac{h_{1}-h_{2}}{h_{1}-h_{2s}}$

The real specific enthalpy at outlet is:

$h_{2} = h_{1} - \eta_{s}\cdot (h_{1}-h_{2s})$

$h_{2} = 3411.4\,\frac{kJ}{kg} - 0.77\cdot (3411.4\,\frac{kJ}{kg} - 2467.32\,\frac{kJ}{kg} )$

$h_{2} = 2684.46\,\frac{kJ}{kg}$

State 2 - Superheated Vapor

$P = 100\,kPa$

$T = 104.3^{\textdegree}C$

$h = 2684.46\,\frac{kJ}{kg}$

$s = 7.3829\,\frac{kJ}{kg\cdot K}$

The mass flow rate is:

$\dot m = \frac{5000\,kW}{3411.4\,\frac{kJ}{kg} -2684.46\,\frac{kJ}{kg}}$

$\dot m = 6.878\,\frac{kg}{s}$

b) The temperature at the turbine exit is:

$T = 104.3^{\textdegree}C$

c) The rate of entropy generation is determined by means of the Second Law of Thermodynamics:

$\dot m \cdot (s_{in}-s_{out}) + \dot S_{gen} = 0$

$\dot S_{gen}=\dot m \cdot (s_{out}-s_{in})$

$\dot S_{gen} = (6.878\,\frac{kg}{s})\cdot (7.3829\,\frac{kJ}{kg\cdot K} - 6.8000\,\frac{kJ}{kg\cdot K} )$

$\dot S_{gen} = 11.8\,\frac{kW}{K}$

4 0

3 years ago

Which of these refers to tempo?

Lilit [14]

The choice that would best describe the word "tempo" would be letter A which states that it is "a pace of music or speed of beats per minute." In addition, a tempo is an important characteristic of music because it is the one who carries the emotions and feelings of the composer towards the music he/she makes.

7 0

3 years ago

Read 2 more answers

The KEOM tower across the street from West is approx. 155 meters high

blondinia [14]

You told your insane friend that it will take the book 5.6 s to get to the ground.

From the question given above, the following data were obtained:

Height (H) = 155 m

<h3>Time (t) =? </h3>

<u>NOTE</u>: Acceleration due to gravity (g) = 10 m/s²

The time taken for the book to get to ground can be obtained as follow:

<h3>H = ½gt²</h3>

155 = ½ × 10 × t²

155 = 5 × t²

<h3>Divide both side by 5</h3>

$t^{2} = \frac{155}{5}\\\\$

t² = 31

<h3>Take the square root of both side </h3>

$t = \sqrt{31}$

<h3>t = 5.6 s</h3>

Thus, the time taken for the book to get to the ground is 5.6 s

Hence, you told your insane friend that it will take the book 5.6 s to get to the ground.

Learn more: brainly.com/question/24903556

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2 years ago

HURRY WILL MARK BRAINLIEST Farha makes the graphic organizer shown to review the characteristics of transistors.

BabaBlast [244]

Answer:

<em>C. It is made from three layers of semiconductors.</em>

<em></em>

Explanation:

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3 years ago