This runner completed a 100 meter race with a time of 13.75 seconds. what was her average speed


Answer 1
Answer: 16.3280 miles per hour I believe 

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(choose the type of science that the following statement implies.) the invention of the yo yo is an example of _____ science.


It is a type of applied science, concretely speaking, Physics applied.

Susan uses Doppler radar to analyze wind patterns in five cities and determine how windy it is. Which statement describes how she benefits from this form of technology? Susan can process wind speed data from different regions. Susan can observe the wind without recording or storing any data. Susan can collect wind data by writing her observations on paper. Susan can travel to each location to determine how fast the wind is blowing.



Susan can process wind speed data from different regions.


A Doppler radar is used in weather forecasting in measuring the direction and speed of objects such as drops of precipitation. It determines if the movement occurring in the atmosphere is horizontally towards or way from the radar. Susan can obtain velocity data about objects at a distance which might be water droplets thus be able to predict a coming weather




just did it


Which of the following is the electron configuration for an electrically neutral atom of oxygen? Use the periodic table if you wish. 1s22s22p6



Please help


The electron configuration for a neutral atom of oxygen would be the final option:

O : 1s^2 2s^2 2p^4.

Knowing that this is a neutral atom of oxygen, and that it posses the same number of electrons and protons, the total number of electrons would be 8. Which can be found out by adding the exponents for each subshell.

1s^2 2s^2

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When an object floats in water, it displaces a volume of water that has a weight equal to the weight of the object. If a ship has a weight of 4753 tons, how many cubic feet of seawater will it displace? Seawater has a density of 1.025 g·cm-3; 1 ton = 2000 lb. (Enter your answer in scientific notation.)



1.63×10⁻²  ft³ is the volume of sea water displaced.


This is the Archimedes's principle, when an object floats in water, it displaces a volume of water that has a weight equal to the weight of the object.

Let's think this formulas

mass . gravity = Weight

density . gravity = Specific weight

The formula for Archimedes's principle is:

Weight of an object = Specific weight of the liquid . submerged volume

To find out the Weight of the ship, we convert the tons to kg.

4753 tons . 1kg / 1×10⁻³ tons = 4753000 kg

gravity = 9.8 m/s²

Weight of the ship = mass . gravity → 4753000 kg . 9.8 m/s² = 46579400 N

To apply the formula, we have to convert the density to kg/m³

1.025 g/cm³ → In 1cm³ we have 1.025 g

1cm³ = 1×10⁻⁶ m³

In 1×10⁻⁶ m³ we have 1.025 g

In 1m³ we would have 1.025×10⁹ g

So 1.025×10⁹ g . 1kg/ 1×10⁻³ g = 1.025×10⁶ kg/m³

Let's go to the formula:

46579400 N = 1.025×10⁶ kg/m³ . 9.8 m/s² . Sumerged volume

46579400 N = 10045000 N/m³ . Sumerged volume

46579400 N / 10045000 m³ /N = Sumerged volume → 4.63 m³

Let's make the final conversion

4.63 m³ . 35.31 ft³ / 1m³ = 1.63×10⁻²  ft³


How many liters of carbon dioxide will be formed from the decomposition of 14.1g of calcium carbonate (at stp)?


Firstly,  according to Ideal Gas Law the volume of 1 mole of a gas at Standard Temperature and Pressure (STP) is 22.4 , ie the value of the molar volume (Vm) is 22.4 /mol.

From the reaction, it can be seen that  and   have the following amount of substance relationship:

From the relationship we can determinate moles of :

Finally, we can calculate the volume of formed CO2:

V( )=nxVm=0.141x22.4=3.16


What happens to the cool and hot zones of a nonluminous flame when the air control valve is closed?


When the air control valve is closed in a nonluminous flame, the flame will turn to a luminous flame.

A nonluminous flame refers to a flame that emits little light in a not usable region of the visible light spectrum.

When the air control valve is closed in the zones of a nonluminous flame, it should be noted that one will not be able to see the zones. Nonluminous flame requires enough oxygen supply. The flame will then turn to a luminous flame.

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When the cool and hot zones of a non luminous flame’s air control valve is closed, the gas in which will be in placed as first and as it encounters air as it was in the mouth of the burner, there will be a presence of incomplete mixing, causing a combustion which would be incomplete and will also lead to a process that can’t be controlled, resulting to flame that is cool.


The percent by mass of copper in CuBr2 is Use mc004-1.jpg. 28.45%. 44.30%. 63.55%. 71.55%.


First, we must find the total mass of CuBr₂:
Mass = 64 + 2 x 80
Mass = 224

Percentage mass of copper = mass of copper x 100 / total mass
Percentage mass of copper = (64 / 224) x 100
Percentage mass of copper = 28.45%

i believe it is A on e2020


What do statistical odds predict that over time In any isolated system of molecules?


This question likely has a set of choices. In the absent of it, I can answer it using the second law of thermodynamic.

The second law of thermodinamy states that an isolated system the entropy will  increase.

Entropy is a measure of the diosrder of the molecules of system.

Then in an isolated system statistical odds predict that molecules will be as mixed (disordered) as they can.

As an example, you can imagin that you add a drop of blue coloarant to a glass of water. If the system will be in pertect order the blue color will remain in a fixed place in the water. But, the reality, and prediction of theory, is that the molecules of the colorant will spread as much as they can and that is the reason why the whole water will be coloured in blue.


Can two atoms with the same mass number ever be isotopes of each other


Two atoms with the same mass number cannot ever be isotopes of each other. If two atoms have the same mass number, then they can be the same element or they have different number of protons and with different number of neutrons. Isotopes are atoms which has the same number of protons in the nucleus but they have different number of neutrons. 


No, two atoms with the same mass number can never be isotopes of each other.


Isotopes always have different mass number and same atomic number. Mass number is the sum of the number of protons and the number of neutrons. Atomic number is the total number of protons. Therefore, isotopes have different number of neutrons but same number of protons. For example, the three isotopes of hydrogen are ¹₁H,²₁H and ³₁H.

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