7. A cyclist starting from rest accelerates at a rate of 6 m/s until she reaches 30 m/s. How long
does it take her to accelerate?

Answer: D. Plutonium-238 is the most stable isotope

Explanation:

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles (such as alpha (α), beta (β), gamma (γ) particles)

General formulas used in decay:

T = duration of decay

t 1/2 = half-life

N₀ = the number of initial radioactive atoms

Nt = the number of radioactive atoms left after decaying during T time

Half-life shows the time it takes for an atom to get half of its initial mass (to decay to half of its initial mass)

The longer the half-life indicates the stability of the atom

Half-life (hr) of isotopes :

Polonium-210  : 3,310

Uranium-237  : 162

Francium-227  : 0.04

Plutonium-238 : 768,000

The half-life value above shows that Plutonium-238 has the longest time, making it the most stable

The longer the half life of an isotope higher will be its stability. Here, among the given isotopes, plutonium - 238 has the greater half life. Hence it is the mist stable one.

Heavy unstable radioactive isotopes undergoes nuclear decay through the emission of charged particles such as alpha or beta. The unstable isotopes then converts to other stable nuclei or to isotopes with more half life.

Half life of a radioactive isotope is the time required to decay the half of initial amount of the isotope. It is inversely proportional to the decay constant of the nuclear decay.

Among the given isotopes, Pu-238 has the longer half life time. Longer half time means more time to get decayed by half then more stability. Thus, Pu-238 is the most stable one.

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Answer:

magnesium oxide

Explanation:

hope this helps

Answer:

Option B: ΔH is (+); endothermic

Explanation:

From the reaction Cl2 → 2Cl(g) given, we can see that the number of moles on the left hand side is 1 while on right hand side, it is 2. This means the number of moles are increasing and it means that the randomness of the system has increased. Also, the bonds are being broken down.

Therefore, the reaction is endothermic. In endothermic reactions, ΔH is positive.

Thus, the correct option is option B.

Answer:

b

Explanation:

ah

Answer:

ACB

Explanation:

Thermal energy is the average sum of all kinetic energy of all the molecules of gases. The correct order of mug in decreasing thermal energy is C>A>B.

Thermal energy is a energy which is possess by a moving object. It is directly proportional to kinetic energy of the molecules. It is very difficult to find the correct value of kinetic energy so we find average kinetic energy. Which is very easy to calculate as compared to calculating kinetic energy. Average kinetic energy is directly proportional to temperature. It is not dependent on the type of gases or mass of gases.

Mathematically,

K.E=2/3KT

Where,

K= Boltzmann constant

T is the temperature

Between A and C whose volume is same, 120°F is the highest temperature so, C will have high thermal energy than A. C will have lowest thermal energy as it has volume larger than that of A and C.

Therefore, the correct order of mug in decreasing thermal energy is C>A>B.

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Answer:

As it is given that

[tex]activity=\lambda= 100\\[/tex]

[tex]Number~of ~counts=100/second\\[/tex]

Using formula

[tex]ln(\frac{N}{N_o})=-\lambda\cdot t\\\\[/tex]

or

[tex]-\frac{ln(\frac{N}{N_o})}{\lambda}= t\\\\[/tex]

where [tex]N=\frac{N_o}{3}[/tex]

[tex]-\frac{ln(\frac{1}{3})}{100}= t\\\\\-\frac{-1.0986}{100}=t\\\\[/tex]

[tex]\frac{1.0986}{100}=t\\1.0986\cdot 10^{-2}seconds=t\\[/tex]

Answer:

where are the options?

Explanation:

Answer:

i feel like the answer is A

Answer: B.

Explanation:

The nucleus is a membrane-enclosed organelle found in most eukaryotic cells. The nucleus is the largest organelle in the cell and contains most of the cell's genetic information (mitochondria also contain DNA, called mitochondrial DNA, but it makes up just a small percentage of the cell's overall DNA content).

Hope this helps!

Answer:

nuke-leus

Explanation:

Answer:

Volume of hydrogen gas formed = 3.1 L

Explanation:

Given data:

Mass of magnesium = 3.00 g

Temperature = room = 27°C (27+273 = 300 K)

Pressure = 1 atm

Volume of hydrogen gas formed = ?

Solution:

Chemical equation:

Mg + H₂SO₄    →       MgSO₄ + H₂

Number of moles of Mg:

Number of moles = mass/molar mass

Number of moles = 3.00 g/ 24 g/mol

Number of moles = 0.125 mol

Now we will compare the moles Mg with hydrogen.

                    Mg             :             H₂

                     1                :              1

                   0.125          :          0.125

Volume of hydrogen:

PV = nRT

1 atm × V = 0.125 mol  ×  0.0821 atm.L /K.mol × 300 k

V = 3.1atm.L/1 atm

V = 3.1 L

Answer:

Yes

Explanation:

Because it was false because it has been the substance abuse permalink

This problem is providing information about the states of matter and a given diagram showing a molecular arrangement it has. Thus, we can start off by analyzing the attached file, which shows molecular arrangements and movements each state exhibits.

Solids are quite organized so that they are able to form molecular networks in which molecules vibrate but do not displace anywhere. Liquid molecules are close enough to have small movements and vibrations but are not able to form any organized network.

Gases, however, exhibit no molecular organization but large movements inside the container whose walls the gas constantly crash against. Plasma do not have any order neither yet it contains ions.

In such a way, since the given diagram do not have any apparent order or ion, we infer this is about a gas that moves into the container and crash against its walls.

Learn more:

Answer:

Both processes produce equal entropy

Explanation:

Three compartments : A , B , C

A to the left, B in center, C on the right

compartment B is filled at 298 k  while A and C is empty

The process that produces more entropy is:  both processes and this is because the system is an isolated system with no heat matter and work exchange with the environment. and also entropy is independent of the path a process follows so either valve been open does not affect the entropy in the system because the change in the internal energy of an isolated system = 0

Answer:

a

Explanation:

Answer:

if an object weighs more than an equal volume of water, it is more dense and will sink, and if it weighs less than an equal volume of water, it is less dense and will float. Remember that the density of water is about 1 g/cm3.

Answer:

0.219 g/mL.

Explanation:

From the question given above, the following data were obtained:

Mass = 25 g

Volume = 114 mL

Density =.....?

Density of a substance is simply defined as the mass of the substance per unit volume of the substance. Mathematically, it is expressed as:

Density = mass /volume

With the above formula, we can obtain the density of the substance given in the question above as follow:

Mass = 25 g

Volume = 114 mL

Density =.....?

Density = mass /volume

Density = 25/114

Density = 0.219 g/mL

Therefore, the density of the substance is 0.219 g/mL

Answer:

the answer is HYPOTHESIS your welcome

Explanation:

Answer:

Explanation: Chemical changes  cause a substance to change into an entirely substance with a new chemical formula. And chemical changes are also known as chemical reaction.

Answer:

it is organism the third one

Answer: the answer is Z

Explanation:

Becuase the order from smallest to largest would be:

Y: Cell

Z: Tissue

W: Organ

X: Organ system

Answer:

25°C + 273.15 = 298.15K , so D.) is the Answer

Explanation:

When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor

Explanation:

When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor

Answer:

3.83%

Explanation:

First, find the average of the measured value.  You should get 286.

291 + 287 + 295 + 281 = 1154

1154/4 = 288.5

Subtract the accepted value (300) from the average measured value (286).  Take the absolute value of your answer.  You should get 14.

288.5 - 300 = -11.5 = 11.5

Divide the difference from the above problem (14) by the accepted value (300).  You should get 0.0467.

11.5/300 = 0.0383

Multiply by 100%.

0.0383 × 100% = 3.83%

The percent error is 3.83%.

Answer:

3.83 percent

Explanation:

Accepted Value = 300 degrees celsius

So since we are given the formula for percentage error,

we know that we have to find the average measured value since the accepted value is already provided

Average Measured Value:

Sum of all measured values / number of measured values

(291 + 287 + 295 + 281) / 4

1154 / 4

288.5 degrees celsius

Now, plugging the values in the given formula:

(average measured value - accepted value) *100 / accepted value

(288.5 - 300) * 100 / 300

-1150 / 300

-3.83 percent

Taking Absolute Value:

3.83 percent

Hence, the average value of the temperature is 3.83 percent less than the accepted value

Answer:

bill gates

Explanation:

Answer:

We have the final answer as

[tex]4.69 \times {10}^{ - 19} \: \: J[/tex]

Explanation:

To find the energy of a photon of this light we use the formula

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question

f = 7.08×10¹⁴ Hz

We have

E = 7.08×10¹⁴ × 6.626 × 10-³⁴

We have the final answer as

[tex]4.69 \times {10}^{ - 19} \: \: J[/tex]

Hope this helps you

Answer:

12 sodium 4 phosphorus 16 oxygen.  makes the table below to determine the number of atoms of each element in the chemical formula 4Ca(ClO3)2.

The elastic potential energy of the spring will be two times greater than the gravitational potential energy of the object.

Answer:

C.) The elastic potential energy of the spring will be two times greater than the gravitational potential energy of the object.

Explanation:

Hope this helps! Sorry if I am wrong. ;-;