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2 months ago

5

An insulated box containing helium gas falls from a balloon 4.5 km above the earth's surface. calculate the temperature rise in

℃ of the helium when box hits the ground. A. 15.2 B. 12.6 C. 25.3 D. 14.1

1 answer:

iogann1982 [368]2 months ago

6 0

The increase in temperature of the helium gas is calculated to be 14.25 K. The helium is located in an insulated box that falls from a height of 4.5 km. As it descends, the potential energy is transformed into internal energy of the helium gas. The equation for temperature change can be expressed as: 10 x 4.5 = 3.15 x ΔT, yielding a temperature increase of ΔT = 14.25 K.

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Effects of biological hazards are widespread. Select the answer options which describe potential effects of coming into contact

pantera1 [306]

Answer:

- Allergic Responses

- Events Posing Life Threats

Explanation:

Biological hazards can originate from a variety of sources such as bacteria, viruses, insects, plants, birds, animals, and humans. These can lead to numerous health issues, which may range from skin allergies and irritations to infections (like tuberculosis or AIDS) and even cancer.

7 0

2 months ago

A liquid food with 12% total solids is being heated by steam injection using steam at a pressure of 232.1 kPa (Fig. E3.3). The p

iogann1982 [368]

Answer:

$m_{s}=20kg/min$

$H_{s}=1914kJ/kg$

Explanation:

A liquid food containing 12% total solids is heated via steam injection at a pressure of 232.1 kPa (see Fig. E3.3). The product starts at a temperature of 50°C and has a flow rate of 100 kg/min, being elevated to a temperature of 120°C. The specific heat of the product varies with its composition as follows:

$c_{p}=c_{pw}(mass fraction H_{2}0)+c_{ps}(mass fraction solid)$ and the

specific heat of the product at 12% total solids is 3.936 kJ/(kg°C). The goal is to calculate the quantity and minimum quality of steam required to ensure that the leaving product has 10% total solids.

Given

Product total solids in ( $X_{A}$ ) = 0.12

Product mass flow rate ( $m_{A}$ ) = 100 kg/min

Product total solids out ( $X_{B}$ ) = 0.1

Product temperature in ( $T_{A}$ ) = 50°C

Product temperature out ( $T_{B}$ ) = 120°C

Steam pressure = 232.1 kPa at ( $T_{S}$ ) = 125°C

Product specific heat in ( $C_{PA}$ ) = 3.936 kJ/(kg°C)

The mass equation is:

$m_{A}X_{A}=m_{B}X_{B}$

$100(0.12)=m_{B}(0.1)\\m_{B}=\frac{100(0.12)}{0.1} =120$

Also $m_{a}+m_{s}=m_{b}\\$

Therefore: $100}+m_{s}=120\\\\m_{s}=120-100=20$

The energy balance equation is:

$m_{A}C_{PA}(T_{A}-0)+m_{s}H_{s}=m_{B}C_{PB}(T_{B}-0)$

$3.936 = (4.178)(0.88) +C_{PS}(0.12)\\C_{PS}=\frac{3.936-3.677}{0.12} =2.161$

$C_{PB}= 4.232*0.9+0.1C_{PS}= 4.232*0.9+0.1*2.161=4.025$ kJ/(kg°C)

By substituting values into the energy equation:

$100(3.936)(50-0)+20H_{s}=120(4.025)}(120-0)$

$19680+20H_{s}=57960\\20H_{s}=57960-19680 \\20H_{s}=38280\\H_{s}=\frac{38280}{20} =1914$

$H_{s}=1914kJ/kg$

From the properties of saturated steam at 232.1 kPa,

$H_{c}$ = 524.99 kJ/kg

$H_{v}$ = 2713.5 kJ/kg

% quality = $\frac{1914-524.99}{2713.5-524.99} =63.5%$

Any steam quality above 63.5% will result in higher total solids in the heated product.

3 0

2 months ago

Describe the grain structure of a metal ingot that was produced by slow-cooling the metal in a stationary open mold.

pantera1 [306]

In the scenario of a metal ingot cooling slowly, the microstructure tends to be coarse. The surface, exposed to higher temperatures for extended periods during cooling, features smaller grain sizes as they have less time to form. However, as we delve deeper into the ingot, the grains gradually extend, leading to equiaxed grain formation at the center.

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2 months ago

In a heat-treating process, a 1-kg metal part, initially at 1075 K, is quenched in a closed tank containing 100 kg of water, ini

mote1985 [299]

Answer:

provided below

Explanation:

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2 months ago

An air-conditioning system is to be filled from a rigid container that initially contains 5 kg of liquid R-134a at 24°C. The val

grin007 [323]

Answer: a) U2 = 164.737kJ/kg

b) Q2 = 22.6kJ

Explanation: see attachment below

6 0

1 month ago