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3 years ago

What is a nanotoxin and what areas can they be found in?

1 answer:

5 0

Nanotoxicology is the study of the toxicity of nanomaterials. Because of quantum size effects and large surface area to volume ratio, nanomaterials have unique properties compared with their larger counterparts that affect their toxicity.

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Calculate the heat flux (in W/m^2) through a sheet of a metal 14 mm thick if the temperatures at the two faces are 350 and 140°C

ExtremeBDS [4]

Answer:

Explanation:

The rate of conductive heat transfer in watts is:

q = (k/s) A ΔT

where k is the heat conductivity, s is the thickness, A is the area, and ΔT is the temperature difference.

Given k = 52.4 W/m/K, s = 0.014 m, and ΔT = 350-140 = 210 K, we can find q/A:

q/A = (52.4 / 0.014) (210)

q/A = 786,000 W/m²

Given that A = 0.42 m², we can find q:

q = (0.42 m²) (786,000 W/m²)

q = 330,120 W

A watt is a Joule per second. Convert to Joules per hour:

q = 330,120 J/s * 3600 s/hr

q = 1.19×10⁹ J/hr

If we change k to 1.8 W/m/K:

q = (k/s) A ΔT

q = (1.8 / 0.014) (0.42) (210)

q = 11,340 J/s

q = 4.08×10⁷ J/hr

If k is 52.4 W/m/K and s is 0.024 m:

q = (k/s) A ΔT

q = (52.4 / 0.024) (0.42) (210)

q = 192,570 J/s

q = 6.93×10⁸ J/hr

5 0

3 years ago

two forces whose magnitude are in ratio of 3:5 gives a resultant of 35N.if the angle of inclination is 60degree.calculate the ma

nadya68 [22]

Answer:

the magnitude of first force = 3 × 5= 15 N

ANd, the magnitude of second force = 5 × 5 = 25 N

Explanation:

The computation of the magnitude of the each force is shown below:

Provided that

Ratio of forces = 3: 5

Let us assume the common factor is x

Now

first force = 3x

And, the second force = 5x

Resultant force = 35 N

The Angle between the forces = 60 degrees

Based on the above information

Resultant force i.e. F = √ F_1^2 +F_2^2 + 2 F_1F_2cos $\theta$

35 = √[(3x)²+ (5x)²+ 2 (3x)(5x) cos 60°]

35 =√ 9x² + 25x² + 15x² (cos 60° = 0.5)

35 = √49 x²

x = 5

So, the magnitude of first force = 3 × 5= 15 N

ANd, the magnitude of second force = 5 × 5 = 25 N

7 0

3 years ago

If measuring experimental results, what can you predict about the work output of a 1200 Watt hair dryer?

Elden [556K]

I am 90% sure it’s A

3 0

3 years ago

Read 2 more answers

how long does it take adrian to reach his destination if his displacement is 253 meters and he walks north with a velocity of 1.

klemol [59]

Velocity = displacement/time

1.6 = 253/t

t = 158.125

It takes them about 158 seconds

4 0

3 years ago

Suppose that the model presented by student 1 is correct. Based on the information provided, what would be the bond angle in a m

Ugo [173]

Question: Predicting the shape of a molecule is relatively straight forward. A molecule's shape will always be determined by the number of electron pairs around the central atom. The number of electron pair corresponds to the number of atoms that are bound to the central atom of the molecule. For example, water contains two hydrogen atom bound to one atom of oxygen, giving the molecule a linear geometry.

Suppose that the model presented by student 1 is correct. Based on the information provided, what would be the bond angle in a molecule of perchlorate ion.

Answer: Suppose that the model presented by student 1 is correct The (perchlorate ion) will be a tetrahedral shape, O-Cl-O bond angle 109.5 due to four groups of bonding electrons and no lone pairs of electrons.

8 0

2 years ago