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umka2103 [35]
3 years ago
15

A sled is at rest at the top of a slope 2 m high. The sled has a mass of 45 kg. What is the sled’s potential energy? (Formula: P

E = mgh)
90 J
56.8 J
441 J
882 J
Chemistry
2 answers:
11Alexandr11 [23.1K]3 years ago
5 0

Answer:

D

Explanation:

olga_2 [115]3 years ago
4 0

Explanation:

Gravitational potential energy

= mgh = (45kg)(9.81N/kg)(2m) = 882J.

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Andrews [41]
Sediment is solid material that is moved and deposited in a new location. Sediment can consist of rocks and minerals, as well as the remains of plants and animals. It can be as small as a grain of sand or as large as a boulder. Sediment moves from one place to another through the process of erosion.
5 0
3 years ago
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Some radioactive nuclides have very short half-lives, for example, I-31 has a half-life of approximately 8 days. Pu-234, by comp
lorasvet [3.4K]

Answer:

Here's what I find.

Explanation:

Iodine-131

Iodine-131 is both a beta emitter and a gamma emitter.

_{53}^{131}\text{I}\longrightarrow \, _{54}^{131}\text{Xe} +\, _{-1}^{0}\text{e} +\, _{0}^{0}\gamma

About 90 % of the energy is β-radiation and 10 % is γ-radiation. Both forms are highly energetic.

The main danger is from ingestion. The iodine concentrates in thyroid gland, where the β-radiation destroys cells up to 2 mm from the tissues that absorbed it.

Both the β- and γ-radiation cause cell mutations that can later become cancerous. Small doses, such as those absorbed from the nuclear disasters in the Ukraine and Japan, can cause cancers years after the original iodine has disappeared.

Plutonium-239

Plutonium-239 is an alpha emitter.

_{94}^{239}\text{U} \longrightarrow \, _{92}^{235}\text{Xe} + \, _{2}^{4}\text{He}

Alpha particles cannot penetrate the skin, so external exposure isn't much of a health risk.

However, they are extremely dangerous when they are inhaled and get inside cells. They travel first to the blood or lymph system and later to the bone marrow and liver, where they cause up to 1000 times more chromosomal damage than beta or gamma rays.

It takes about 20 years for plutonium to be eliminated from the liver around 50 years for from the skeleton, so it has a long time to cause damage.

6 0
3 years ago
What is the percent yield of a reaction in which 200. g of phosphorus trichloride reacts with excess water to form 91.0 g of hcl
Snowcat [4.5K]
Answer is: <span>yield of a reaction is 56,4%.
</span>Chemical reaction: PCl₃ + 3H₂O → 3HCl + H₃PO₃.
m(PCl₃) = 200 g.
m(HCl) = 91,0 g.
n(PCl₃) = m(PCl₃) ÷ M(PCl₃).
n(PCl₃) = 200 g ÷ 137,33 g/mol.
n(PCl₃) = 1,46 mol.
n(HCl) = m(HCl) ÷ M(HCl).
n(HCl) = 91 g ÷ 36,45 g/mol.
n(HCl) = 2,47 mol.
From reaction: n(PCl₃) : n(HCl) = 1 : 3.
n(HCl) = 1,46 mol · 3 = 4,38 mol.
Yield of reaction: 2,47 mol ÷ 4,38 mol · 100% = 56,4%.
4 0
3 years ago
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Large telescopes have revealed information about the motions of stars. They helped scientists realize that most stars and galaxi
fiasKO [112]

Answer:b

Explanation:sorry if I’m wrong

5 0
3 years ago
Under certain conditions Argon gas diffuses at a rate of 3.2 cm per second under the same conditions an unknown gas diffuses at
kozerog [31]

Answer:

20 g/mol

Explanation:

We can use <em>Graham’s Law of diffusion</em>:

The rate of diffusion (<em>r</em>) of a gas is inversely proportional to the square root of its molar mass (<em>M</em>).

r = \frac{1 }{\sqrt{M}}

If you have two gases, the ratio of their rates of diffusion is

\frac{r_{2}}{r_{1}} = \sqrt{\frac{M_{1}}{M_{2}}}

Squaring both sides, we get

(\frac{r_{2}}{r_{1}})^{2} = \frac{M_{1}}{M_{2}}

Solve for <em>M</em>₂:

M_{2} = M_{1} \times (\frac{r_{1}}{r_{2}})^{2}

M_{2} = \text{39.95 g/mol} \times (\frac{\text{3.2 cm/s}}{\text{4.5 cm/s}})^{2}= \text{39.95 g/mol} \times (0.711 )^{2}

= \text{39.95 g/mol} \times 0.506 = \textbf{20 g/mol}

7 0
3 years ago
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