Sarah is running a race and is almost to the finish line. In the last 5 seconds, her velocity changes from 2m/s to 4m/s. What is her average acceleration during the last 5 seconds of the race?

Answers

Answer 1

Answer:

[tex]\boxed {\boxed {\sf a= \frac {2}{5} \ or \ 0.4 \ m/s^2}}[/tex]

Explanation:

Acceleration is found by dividing the change in velocity by the time. The formula is:

[tex]a= \frac {v_f-v_i}{t}[/tex]

where [tex]v_f[/tex] is the final velocity, [tex]v_i[/tex] is the initial or starting velocity, and [tex]t[/tex] is the time.

Her velocity changes from 2 meters per second to 4 meters per second in the 5 seconds. Therefore:

[tex]v_f= 4 \ m/s \\v_i= 2 \ m/s \\t=5 \ s[/tex]

Substitute the values into the formula.

[tex]a= \frac { 4 \ m/s- 2 \ m/s}{5 \ s}[/tex]

Solve the numerator and subtract.

[tex]a= \frac { 2 \ m/s}{5 \ s}[/tex]

Divide.

[tex]a= \frac{2}{5} \ m/s/s= \frac{2}{5} \ m/s^2[/tex]

This can also be written as a decimal.

[tex]a=0.4 \ m/s^2[/tex]

Her average acceleration during the last 5 seconds of the race is 2/5 or 0.4 meters per square second.

Answer 2

Answer:

Solution :-

Here

Initial velocity = 2 m/s

Final velocity = 4 m/s

Time = 5 sec

v = u + at

4 = 2 + a(5)

4 - 2 = a(5)

2 = 5a

2/5 = a

Hence, acceleration is 2/5 m/s²


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Answer:True

Explanation:

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The scientist who wrote the universal law of gravitation was Sir Isaac Newton.

The scientist that wrote the universal law of gravitation was Isaac Newton.

What is the universal law of gravitation?

The universal law of gravitation states that every object in this universe attracts every other object around it with a force, whose magnitude is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them.

The universal law of gravitation was first published by the scientist Issac Newton in the year 1687.

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A photon with a wavelength of 397nm is emitted from an electron in energy level 7 of a Hydrogen atom. What is the new energy level of the electron?

Answers

Answer:

New energy level is n = 2

Explanation:

ΔE = energy released by e⁻ transition n = 7 to n(final) = - h·c/λ

h = Planck's Constant = 6.63 x 10⁻³⁴ j·s

c = speed of light in vacuum = 3 x 10⁸ m/s

λ = wavelength = 397 nm = 3.97 x 10⁻⁷ m

ΔE = - (6.63 x 10⁻³⁴j·s )(3 x 10⁸ m/s)/(3.97 x 10⁻⁷ m) = - 5.01 x 10⁻¹⁹ joule

Note: this is the transitional energy 'released' by the electron moving from n = 7 energy level to n(final) energy level. As released energy, the system should be represented by an exothermic process hence, the negative value for ΔE = - h·c/λ. The equivalent amount of energy is an absorption of electromagnetic energy (EMR) to promote the electron from n(final) to n = 7 and this would be endothermic as noted with a +h·c/λ .

The Bohr Model of the electron behavior postulates electron transitions by the release of a 'discrete' amount of EMR as emission spectra defined by the expression ...

ΔE = E(final) - E(initial) => E(final) = ΔE + E(initial)

E(n) = positional (potential) energy content of electron while in energy level n and is defined by the expression E(n) = -R(H)/n²

R(H) = Rydberg Constant = 2.18 x 10⁻¹⁸ joules

n = positional energy level (in this case) = 7

E₇ = -2.18 x 10⁻¹⁸ j / (7)² = -4.45 x 10⁻²⁰ j (potential energy of n = 7 electron)

E(final) = ΔE + E₇ = (-5.01 x 10⁻¹⁹ j)  + (-4.45 x 10⁻²⁰ j) = -4.455 x 10⁻¹⁹ j

E(final) = -R(H)/n²

=> n = SqrRt[R(H)/E(final)] = SqrRt[(-2.18 x 10⁻¹⁸ j)/(-4.455 x 10⁻¹⁹)] ≅ 2

New energy level is n = 2


Tides are the result of forces exerted on Earth's oceans, mostly by which celestial body?
The Sun
Jupiter
The Moon
Venus

Answers

The answr is the moon

Answer:

Explanation:

The moon

if people are blind can they dream

Answers

Answer:

yeah they dream in weird shapes mostly I think. unless they weren't born blind then they dream normally I think

Answer:

Kind of, our dreams refer to what we see, but blind people can't see, they might have dreams what the world might look like

How many moles are represented by 86.5 g of Ca(OH)2?
*please help fast*

Answers

Answer:

30 2 the second power

Explanation:

Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.

What is Calcium Hydroxide?

Its chemical formula is Ca(OH)2. When calcium oxide and water are combined, it produces.

There are two hydroxide ions (OH) in the molecule for every calcium ion (Ca2+). The substance is ionic, and both electrolytic and aqueous dissociations result in calcium and hydroxide ions.

When water is added to dry portland cement to create concrete, this reaction takes place, and the mixture warms up and releases heat. An alternative method of manufacturing entails an aqueous double displacement reaction between sodium hydroxide and calcium chloride.

Therefore, Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.

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Which One Is the Wrong One?

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Answer:

I would say the second one it's the wrong

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B.scientists watching bacteria divide

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C is the answer To the question

What force pulls the water down hill in a watershed, preventing it from going
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Answer:

gravity

Explanation:

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Answer:

Gravity is the answer.

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C. THERE YA GOOOOOII lol

what particle has a mass & charge?

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b. beta particle
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Answers

Answer:

A. Alpha Particle

Explanation:

I think i could be wrong

can any one solve this quiz plz​

Answers

Answer:

1. It is stoichiometric.

2. O2 is the limiting reactant.

3. 9.0 g of C2H6 remain unreacted.

4. 17.6 g of CO2.

5. 85.2%.

Explanation:

Hello there!

In this case, for the given chemical reaction:

[tex]2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O[/tex]

We can see that:

1. It is stoichiometric and is balanced because the reactants yields the products according to the law of conservation of mass.

2. In this part, it is possible to calculate the moles of ethane by using its molar mass:

[tex]n_{C_2H_6}=15g*\frac{1molC_2H_6}{30.08g} =0.50molC_2H_6[/tex]

And the moles of oxygen by knowing that one mole is contained in 22.4 L at STP:

[tex]n_{O_2}=\frac{1mol}{22.4L} *15.68L=0.7molO_2[/tex]

Thus, by calculating the moles of carbon dioxide product by each reactant, we can identify the limiting one:

[tex]n_{CO_2}^{by\ C_2H_6}=0.50molC_2H_6*\frac{4molCO_2}{2molC_2H_6} =1.0molCO_2\\\\n_{CO_2}^{by\ O_2}=0.70molO_2*\frac{4molCO_2}{7molO_2} =0.4molCO_2\\[/tex]

Thus, since oxygen yields the fewest moles of CO2 product, we infer it is the limiting reactant.

3. In this part, we calculate the mass of C2H6 that actually react first:

[tex]m_{C_2H_6}^{reacted}=0.4molCO_2*\frac{2molC_2H_6}{4molCO_2}*\frac{30.08gC_2H_6}{1molC_2H_6} =6.0gC_2H_6[/tex]

Thus, the leftover of ethane (C2H6) as the excess reactant is:

[tex]m_{C_2H_6 }^{leftover}=15g-6.0g=9.0g6.0C_2H_6[/tex]

4. Since 0.4 moles of carbon dioxide were produced, we use its molar mass to calculate the mass as its theoretical yield:

[tex]m_{O_2}^{theoretical}=0.4molCO_2*\frac{44gCO_2}{1molCO_2}=17.6gCO_2[/tex]

5. Finally, the percent yield is gotten by dividing the actual yield by the theoretical one:

[tex]Y=\frac{15g}{17.6}*100\%\\\\Y=85.2\%[/tex]

Best regards!

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Answer:

ily

Explanation:

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Select one:
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b.Hydronium ion (H3O+)
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Answers

Answer:

D - Hydroxide Ion (OH-)

Explanation:

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Answer:

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The equation for this reaction is shown below.
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Answers

Answer:

[tex] \frac{60}{28} = \frac{15}{7} [/tex]

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Answers

Answer:

recessive trait

Answer:

recessive

Explanation:

Color blindness is a sex-linked, recessive trait.

hope this helps and is right :)

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Answer:Gravity and inertia

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The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions.

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Solute refers to substances or liquid which can readily dissolve in a solvent. It's concentration is lower to that of solvent.

Therefore, The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions

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Answer:

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Explanation:

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Answers

Answer:

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Answers

Answer:

Fe(s) + Cu2+(aq) ===> Fe2+(aq) + Cu(s)

Answer:

2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)

Explanation:

2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)

How does energy from the Sun drive the cycling of matter?

Answers

Answer:

solar energy drives the cycle by evaporating water from the oceans, lakes, rivers, and soil. As liquid water evaporates or transpires, it forms water vapor and clouds, where water droplets eventually gain enough mass to fall back to Earth as precipitation.

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Answer:

Answers of the greenhouse effect 1 ,3 and 4

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Answers

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Explanation:

To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

where,

[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.

[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.

We are given:

[tex]V_1=100.0L\\T_1=135^oC=(135+273)K=408K\\V_2=?\\T_2=72.0^0C=(72.0+273)K=345K[/tex]

Putting values in above equation, we get:

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Thus the volume of gas is 84.6 L at [tex]72.6^0C[/tex]

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C) covalent bond

D) salt

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Salt - Na Cl
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What dose the T-cell attack

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Answer:

killer T-cell find and destroy infected cells that have been turned into virus-making factories

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Answers

Answer:

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

Explanation:

How can a chemical reaction be sped up? Select from the drop-down menu to correctly complete the statement. Add a Choose... that is unaffected by a reaction. the choices are, A: catalyst B: coefficient C: product

Answers

Answer:

A: catalyst

Explanation:

In Chemistry, the rate of reaction of chemical elements (reactants) can be sped to produce a chemical compound or elements (products), through the addition of a catalyst that is unaffected by the reaction.

This ultimately implies that, to speed up a chemical reaction, add a catalyst that is unaffected by a reaction.

For example, an enzyme refers to a biological catalyst that is typically used to speed up (accelerate) the rate of a chemical reaction by lowering the activation energy of its reactants.

An enzyme can be defined as a biological catalyst that typically lowers the activation energy of a biological reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.

Generally, an increase in temperature increases or speeds up the rate of a reaction while low temperature limits or reduces the rate of a reaction. The optimal temperature for enzymes in the human body is around 37 degrees celsius.

help please and show work!

Answers

Answer:

Mg + 2HCl → MgCl2 + H2

Explanation:

Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2

C time
2. An instrument used to measure force is
B. spring balance
A ruler
D) wind vane
C. thermometer
of ford​

Answers

Answer:

B. Spring balance - a device used for measuring the weight or force of gravity acting on an object.

Explanation:

A Force is any interaction that changes the motion or position of an obkpjectbthatbit is interacting with. Whenever there is an interaction between two objects, there is a force exerted by each of the objects on one themselves.

Forces are generally divided into contact forces and non-contact over field forces.

In contact forces, the two objects physically in contact with each other. Examples of contact forces are push or pull forces, frictional forces, tensional forces, spring forces, etc.

Non-contact forces are forces in which the two objects interacting do no need to be physically in contact with one another. Examples include, gravitational forces, magnetic forces, electrical forces, etc.

Instruments used in measuring forces are known as force gauges.

From the instruments listed above:

A. A ruler is an instrument used in measuring length

B. Spring balance is a device used for measuring the weight or force of gravity acting on an object.

C. A thermometer is an instrument used in measuring temperature

D. A windbvane is an instrument used in measuring wind direction.

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