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kolbaska11 [484]
2 years ago
6

Who was the man who lived from 460B.C.–370B.C. and was among the first to suggest the idea of atoms?

Physics
1 answer:
ch4aika [34]2 years ago
6 0
C. Democritus was a Greek philosopher who defined the concept of atoms and is the only one of the answer choices who lived during that time period.
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True or false: Scientific models are always built to scale, and are fully functional representations of the product they are tes
vodka [1.7K]

Answer:

False

Explanation:

Scientific models are not always built to scale and may not be fully accurate

3 0
2 years ago
200-grams of computer chips with a specific heat of 0.3 kJ/kg·K are initially at 25°C. These chips are cooled by placement in 0.
balu736 [363]

Answer:

a. -0.01324 kJ/K,  b.  = 0.03233 kJ/K , c.  = 0.01909, Yes the process is possible

Explanation:

Heat transfer will occur between the chip and the surrounding fluid. Then, finally they will attain a common equilibrium temperature and heat transfer will stop. Now, if we assume that, after heat transfer, chip will attain the temperature of fluid, that is, -34 C,, So , to check whether this is possible

Amount of energy lost by the chip = m . c . (T(i) - T(f))

= 0.2 x 0.3 (25 + 34) = 3.54 KJ

Now, to evaluate the final state of the fluid, after the heat transfer completion,

Energy Gained = m(mew final – mew initial) = m[(μf+ x . μfg) - μf]

Note that heat transfer will change the internal energy of the fluid. Do not consider enthalpy change, as this is not a problem involving fluid flow in and out of the system

M[(μf+ x . μfg) - μf] = m(xμfg)

<u>Energy gained by the fluid will be equal to the energy lost by the chip (No energy loss to the surroundings)</u>

3.54 = 0.1 . X x 203.29

<u>x = 0.1741, which is the dryness fraction of fluid at the final state.</u>

Observe that the total energy lost by the chips is 3.45 kJ and fluid R-134a has got its value of mew fg at -34 C which is = 203.29 kJ/kg

So for 0.1kg of R-134a

0.1 x μfg= <u>20.329 kJ, which is much greater than 3.45 kJ</u>, therefore, it is certain that the state of fluid will be at -34 C only and at the saturation pressure of 69.56 KPa. So the chip will come to attain the temperature of -34 C.  

a. Write the equation for the change of entropy in the chips

ΔSchips = mchips . c . ln(T2/T1), where mc is the mass of chips, c is the specific heat of chips, T2 is the temperature at state 2 and T1 is the temperature at state 1

Substitute mc = 0.2 kg, c = 0.3kJ/kg.K, T1 = 25 + 273, T2 = -34 + 273

delSchips = 0.2 x 0.3 x ln [(-34+273)/ (25+273)]

= -0.01324 kJ/K

There fore the change in entropy of the chips is -0.01324 kJ/K

b. Entropy change of fluid R- 134a

ΔS2 = m[Sfinal – S initial]

= m[Sf + x . Sfg - Sf]

= 0.2 x (0.1741 x 0.92859)

= 0.03233 kJ/K

c. Calculate the total change in the entropy of the entire system

delS = delSchips + delSR -134a

= -0.01324 + 0.03233

= 0.01909

<u>Since the total change in entropy of the entire system is positive that exactly explains that the actual processes are happening in the direction of increase of entropy therefore, the process is possible.</u>

<u />

6 0
3 years ago
Which action will decrease the gravitational force between two objects?
WITCHER [35]

Answer:

It’s D

Explanation:

6 0
3 years ago
In which direction is the magnetic force acting on the charge? into the screen out of the screen up down
Harrizon [31]

The direction in which the magnetic force is acting on the charge is upwards.

<h3>What is Magnetic force?</h3>

This is the attraction and repulsion which usually occurs during the motion of electrically charged particles.

In the magnetic field, the charge is moving to the left. Therefore the direction the magnetic force is acting on the charge is upwards which is gotten via right hand rule.

Read more about Magnetic force here brainly.com/question/25932320

#SPJ1

4 0
1 year ago
Provide two ways that objects can become charged
kap26 [50]

Answer:

friction, conduction and induction

Explanation:

Had it in class I had it correct hope this helps.

8 0
2 years ago
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