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3 years ago

Which of these best explains why a paper clip can float on water? A)Water has a very high specific heat.

Chemistry

2 answers:

stiks02 [169]3 years ago

3 0

Answer:

The answer is d. water molecules near the surface produce more buoyant force than water molecules within the liquid

Explanation: Surface tension is defined as the attraction on the water of like particles to one another. Water molecules on a surface undergoes cohesion or the sticking together of one molecule to another of the same material.

Debora [2.8K]3 years ago

3 0

Answer:

D)Water molecules near the surface produce more buoyant force than water molecules within the liquid.

Explanation:

Buoyant force that is provided by water molecules such that the object can float on the surface of the water. According to Archimedes principle for flotation to occur the buoyant force must be equal to the weight of the object. If the buoyant force is less than the weight of the object, then the object will sink.

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9. The times of first sprinkler activation (in seconds) for a series of tests of fire-prevention sprinkler systems that use aque

Nezavi [6.7K]

This question is incomplete, the complete question is;

The times of first sprinkler activation (in seconds) for a series of tests of fire-prevention sprinkler systems that use aqueous film-forming foam is as follows; 27 41 22 27 23 35 30 33 24 27 28 22 24

( see " use of AFFF in sprinkler systems," Fire technology, 1975: 5)

The system has been designed so that the true average activation time is supposed to be at most 25 seconds.

Does the data indicate the design specifications have not been met?

Test the relevant hypothesis at significance level 0.05 using the P-value approach

Answer:

since p-value (0.042299) is lesser than the level of significance ( 0.05)

We Reject Null Hypothesis

Hence, There is no sufficient evidence that the true average activation time is at most 25 seconds

Explanation:

Given the data in the question;

lets consider Null and Alternative hypothesis;

Null hypothesis H₀ : There is sufficient evidence that the true average activation time is at most 25 seconds

Alternative hypothesis H₁ : There is no sufficient evidence that the true average activation time is at most 25 seconds

i.e

Null hypothesis H₀ : μ ≤ 25

Alternative hypothesis H₁ : μ > 25

level of significance σ = 0.05

first we determine the sample mean;

$x^{bar}$ = $\frac{1}{n}$ ∑ $x_{i}$

where n is sample size and ∑ $x_{i}$ is summation of all the sample;

= $\frac{1}{13}$ ( 27 + 41 + 22 + 27 + 23 + 35 + 30 + 33 + 24 + 27 + 28 + 22 + 24 )

= $\frac{1}{13}$ ( 363

sample mean $x^{bar}$ = 27.9231

next we find the standard deviation

s = √( $\frac{1}{n-1}$ ∑( $x_{i}-x^{bar}$ )²

x ( $x_{i}-x^{bar}$ ) ( $x_{i}-x^{bar}$ )²

27 -0.9231 0.8521

41 13.0769 171.0053

22 -5.9231 35.0831

27 -0.9231 0.8521

23 -4.9231 24.2369

35 7.0769 50.0825

30 2.0769 4.3135

33 5.0769 25.7749

24 -3.9231 15.3907

27 -0.9231 0.8521

28 0.0769 0.0059

22 -5.9231 35.0831

24 -3.9231 15.3907

sum 378.9229

so ∑( $x_{i}-x^{bar}$ )² = 378.9229

∴

s = √( $\frac{1}{13-1}$ ×378.9229 )

s = √31.5769

standard deviation s = 5.6193

now, the Test statistics

t = ( $x^{bar}$ - μ ) / $\frac{s}{\sqrt{n} }$

we substitute

t = ( 27.9231 - 25 ) / $\frac{5.6193}{\sqrt{13} }$

t = 2.9231 / 1.5585

t = 1.88

now degree of freedom df = n - 1 = 13 - 1 = 12

next we calculate p-value

p-value = 0.042299 ( using Execl's ( = TDIST(1.88,12,1)))

Here x=1.88, df=12, one tail

now we compare the p-value with the level of significance

since p-value (0.042299) is lesser than the level of significance ( 0.05)

We Reject Null Hypothesis

Hence, There is no sufficient evidence that the true average activation time is at most 25 seconds

3 0

3 years ago

The picture represents the process that produces most of the energy used by living organisms on Earth. Which process is represen

forsale [732]

Wheres the pic i cant answer without the pic

6 0

3 years ago

Read 2 more answers

Compared to our solar system, the universe is

GuDViN [60]

Answer: Massive

Explanation: There are many galaxies out in the universe and it's possible they go on indefinitely. Out of all of these, our solar system is very very tiny. As an analogy, our universe would be like an atom which are the the smallest units of matter. There are many other galaxies that we just haven't been able to discover but they are there.

3 0

3 years ago

Perform the following operation

Yanka [14]

Taking into account the scientific notation, the result of the sum is 10.84300×10³.

Scientific notation

First, remember that scientific notation is a quick way to represent a number using powers of base ten.

The numbers are written as a product:

a×10ⁿ

where:

a is a real number greater than or equal to 1 and less than 10, to which a decimal point is added after the first digit if it is a non-integer number.
n is an integer, which is called an exponent or an order of magnitude. Represents the number of times the comma is shifted. It is always an integer, positive if it is shifted to the left, negative if it is shifted to the right.

Sum in scientific notation

You want to add two numbers in scientific notation. It should be noted that when the numbers to be added do not have the same base 10 exponent, the base 10 power with the highest exponent must be found. In this case, the highest exponent is 3.

Then all the values are expressed as a function of the base 10 exponent with the highest exponent. In this case: 9.7300×10²= 0.97300×10³

Taking the quantities to the same exponent, all you have to do is add what was previously called the number "a". In this case:

0.97300×10³ + 9.8700×10³= (0.97300+ 9.8700)×10³= 10.84300×10³

Finally, the result of the sum is 10.84300×10³.

Learn more:

3 0

2 years ago

This element is a metalloid of Group IV. It has ____ valence electrons on the third energy level. Its name is ____, symbol____.

babymother [125]

Answer: 4 valence electrons, Silicon, Si, 14, 28.0855, 14

Explanation:

3 0

3 years ago