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3 years ago

Make the following conversion: 34.9 cL = _____ hL

1 answer:

8 0

We know that: 1 L = 100 cL. Or 1 cL = 0.01 L. Then we will make the conversion: 34.9 cL = 34.9 / 100 L = 0.349 L. Also: 1 hL = 100 L. 0.349 L = 0.349 / 100 hL = 0.00349 hL. This can be also written as: 3.49 * 10^(-3) hL ( in the scientific notation ). Answer: 3.49 cL = 0.00349 hL

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4 Suggest four ways in which participating in physical activities can build healthy relationship? 5.Show in two ways the influeb

valina [46]

Answer:

Increases levels of well-being neurotransmitters
Improves fitness
Improves mental health
Reduces the risk of developing diseases

Explanation:

Performing physical activities helps to build a healthy relationship with yourself, in the sense that physical activity promotes health at all levels. Health is a set of physical, mental and social well-being, so physical activity reaches all these levels and increases the quality of life for a person as a whole.

There are several types of physical activities that can be performed and you can choose the one that best fits your preferences and routine. A walk for example can be done in any safe place and at any time and it already helps in improving physical conditioning, in receiving serotonin and endorphins, in reducing blood pressure and protecting the heart and in improving mental health.

So the ideal is for each person to set their own goals in relation to their health and seek to achieve them, either to have a better quality of life, to socialize more with people, to prevent diseases, etc.

8 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)

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

3.54 = 0.1 . X x 203.29

x = 0.1741, which is the dryness fraction of fluid at the final state.

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= 20.329 kJ, which is much greater than 3.45 kJ, 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

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.

6 0

3 years ago

Can force be two-dimensional?

nata0808 [166]

Answer:

Yes

Explanation:

Just as motion in two dimensions introduced vectors, forces in two dimensions also involve more involved issues.

3 0

2 years ago

A car is going along a circular road at a constant speed. The radius of the curve is 242 m, and the car takes 1.3 minutes to com

Dvinal [7]

Answer:

$a_c=1.57\frac{m}{s^2}$

Explanation:

In order to find its centripetal acceleration we need to use the next equation:

$a_c=\frac{v^2}{r}$

So, we need to find its velocity in first place. Considering that the time T required for one complete revolution is called the period. For constant speed is given by:

$T=\frac{2\pi r}{v}$