Answer:
i am pretty sure the answer is a
Explanation: because the airplane's flight time has to be the independent variable for it to affect the dependent variable that is the speed of how fast the airplane is going.
Convection is where the heat source heats the air, and the air transfers the heat to object. Some people prefer to heat their marshmallow through convection, this is achieved by holding the marshmallow high above the flames where the heated air is rising, transforing the heat into the marshmallow.
Explanation:
(a) The given data is as follows.
Load applied (P) = 1000 kg
Indentation produced (d) = 2.50 mm
BHI diameter (D) = 10 mm
Expression for Brinell Hardness is as follows.
HB = ![\frac{2P}{\pi D [D - \sqrt{(D^{2} - d^{2})}]}](https://tex.z-dn.net/?f=%5Cfrac%7B2P%7D%7B%5Cpi%20D%20%5BD%20-%20%5Csqrt%7B%28D%5E%7B2%7D%20-%20d%5E%7B2%7D%29%7D%5D%7D)
Now, putting the given values into the above formula as follows.
HB = = ![\frac{2 \times 1000 kg}{3.14 \times 10 mm [D - \sqrt{((10 mm)^{2} - (2.50)^{2})}]}](https://tex.z-dn.net/?f=%5Cfrac%7B2%20%5Ctimes%201000%20kg%7D%7B3.14%20%5Ctimes%2010%20mm%20%5BD%20-%20%5Csqrt%7B%28%2810%20mm%29%5E%7B2%7D%20-%20%282.50%29%5E%7B2%7D%29%7D%5D%7D)
= 
= 200
Therefore, the Brinell HArdness is 200.
(b) The given data is as follows.
Brinell Hardness = 300
Load (P) = 500 kg
BHI diameter (D) = 10 mm
Indentation produced (d) = ?
d = ![\sqrt{(D^{2} - [D - \frac{2P}{HB} \pi D]^{2})}](https://tex.z-dn.net/?f=%5Csqrt%7B%28D%5E%7B2%7D%20-%20%5BD%20-%20%5Cfrac%7B2P%7D%7BHB%7D%20%5Cpi%20D%5D%5E%7B2%7D%29%7D)
= ![\sqrt{(10 mm)^{2} - [10 mm - \frac{2 \times 500 kg}{300 \times 3.14 \times 10 mm}]^{2}}](https://tex.z-dn.net/?f=%5Csqrt%7B%2810%20mm%29%5E%7B2%7D%20-%20%5B10%20mm%20-%20%5Cfrac%7B2%20%5Ctimes%20500%20kg%7D%7B300%20%5Ctimes%203.14%20%5Ctimes%2010%20mm%7D%5D%5E%7B2%7D%7D)
= 4.46 mm
Hence, the diameter of an indentation to yield a hardness of 300 HB when a 500-kg load is used is 4.46 mm.
Answer:
Hydrosulfuric acid will act as limiting reactant.
Explanation:
Given data:
Mass of iron(III) chloride = 3243.0 g
Mass of hydrosulfuric acid = 511.8 g
Limiting reactant = ?
Solution:
Chemical equation:
2FeCl₃ + 3H₂S → Fe₂S₃ + 6HCl
Number of moles of iron(III) chloride:
Number of moles = mass/molar mass
Number of moles = 3243.0 g/ 162.2 g/mol
Number of moles = 20 mol
Number of moles of hydrosulfuric acid:
Number of moles = mass/molar mass
Number of moles = 511.8 g/ 34.1 g/mol
Number of moles = 15 mol
Now we will compare the moles of both reactant with products
FeCl₃ : Fe₂S₃
2 : 1
20 : 1/2 ×20 = 10
FeCl₃ : HCl
2 : 6
20 : 6/2 ×20 = 60
H₂S : Fe₂S₃
3 : 1
15 : 1/3 ×15 = 5
H₂S : HCl
3 : 6
15 : 6/3 ×15 = 30
Hydrosulfuric acid producing less number of moles of product thus, it will act as limiting reactant.
Radioactive isotopes eventually decay, or disintegrate, to harmless materials. Some isotopes decay in hours or even minutes, but others decay very slowly. Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). <u>Plutonium-239 has a half-life of 24,000 years.</u>
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<h3>What is radioactive decay? </h3>
Radioactive decay is the emission of energy in the form of ionizing radiation. The ionizing radiation that is emitted can include alpha particles, beta particles and/or gamma rays. Radioactive decay occurs in unbalanced atoms called radionuclides.
Elements in the periodic table can take on several forms. Some of these forms are stable; other forms are unstable. Typically, the most stable form of an element is the most common in nature. However, all elements have an unstable form. Unstable forms emit ionizing radiation and are radioactive. There are some elements with no stable form that are always radioactive, such as uranium. Elements that emit ionizing radiation are called radionuclides.
Learn more about Radioactive decay
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