A tow truck does 10,000 J of work in 5 seconds. Calculate the power.

describe how astronomers are able to use the light from a distant star to determine what elements make up the stars.

dlinn [17]

Answer:

The spectra of the Sun and stars exhibited bright and dark lines called Fraunhofer lines. These were shown to be caused by elements emitting or absorbing light at specific wavelengths. Because each element emits or absorbs light only at specific wavelengths, the chemical composition of stars can be determined.

7 0

3 years ago

What function does this cytoplasm perform in a plant and animal cells

PtichkaEL [24]

Answer:

It helps shape, while holding and keeping organelles in their place.

Explanation:

6 0

3 years ago

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A tank contains 200 gallons of water in which 300 grams of salt is dissolved. A brine solution containing 0.4 kilograms of salt

Nadusha1986 [10]

Answer:

<h3>Therefore, after long period of time 80kg of salt will remain in tank</h3>

Explanation:

given amount of salt at time t is A(t)

initial amount of salt =300 gm =0.3kg

=>A(0)=0.3

rate of salt inflow =5*0.4= 2 kg/min

rate of salt out flow =5*A/(200)=A/40

rate of change of salt at time t , dA/dt= rate of salt inflow- ratew of salt outflow

$dA/dt=2-(A/40)\\\\dA=2dt-(A/40)dt\\\\dA+(A/40)dt=2dt$

integrating factor

$=e^{\int\limits (1/40) \, dt}$

integrating factor $=e^{(1/40)t}$

multiply on both sides by $=e^{(1/40)t}$

$dAe^{(1/40)t}+(A/40)e^{(1/40)t} dt =2e^{(1/40)t}t\\\\(Ae^{(1/40)t})=2e^{(1/40)t}t$

integrate on both sides

$\int\limits(Ae^{(1/40)t})=\int\limits2e^{(1/40)t}dt\\\\(Ae^{(1/40)t})=2*40e^{(1/40)t}+C\\\\A=80+(C/e^{(1/40)t})\\\\A(0)=0.3\\\\0.3=80+(C/e^{(1/40)t}^*^0)\\\\0.3=80+(C/1)\\\\C=0.3-80\\\\C=-79.7\\\\A(t)=80-(79.7/e^{(1/40)t})$

b)

after long period of time means t - > ∞

${t \to \infty}\\\\ \lim_{t \to \infty} A_t \\\\ \lim_{t \to \infty} (80)-(79/{e^{(1/40)t}}\\\\=80-(0)\\\\=80$

<h3>Therefore, after long period of time 80kg of salt will remain in tank</h3>

6 0

3 years ago

tres pensamientos negativos sobre el C0Vid-19 que se vive en la actualidad y luego transformemos a pensamientos positivos.

katrin2010 [14]

Answer:

Bueno,

Explanation:

Tres pesnamientos negativos sobre el C0Vid-19 son,

- Encerrados en la casa

- Tener que ponerse mascara

- Todos los lugares divertidos cerrados

Convertidos en positivos:

- Pasamos mas tiempo de calidad en familia.

- Nos protejemos unos a otros.

- Descansan un poco todas las personas que se han pasado toda la vida trabajando.

7 0

4 years ago

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A 1.25 g sample of aluminum is reacted with 3.28 g of copper (II) sulfate. What is the limiting reactant?

KengaRu [80]

Answer:

d. Copper (II) sulfate

Explanation:

Given data:

Mass of Al = 1.25 g

Mass of CuSO₄ = 3.28 g

What is limiting reactant = ?

Solution:

Chemical equation:

2Al + 3CuSO₄ → Al₂ (SO₄)₃ + 3Cu

Number of moles of Al:

Number of moles = mass/molar mass

Number of moles = 1.25 g/ 27 g/mol

Number of moles = 0.05 mol

Number of moles of CuSO₄:

Number of moles = mass/molar mass

Number of moles = 3.28 g/ 159.6 g/mol

Number of moles = 0.02 mol

now we will compare the moles of reactant with product.

Al : Al₂ (SO₄)₃

2 : 1

0.05 : 1/2×0.05=0.025 mol

Al : Cu

2 : 3

0.05 : 3/2×0.05 = 0.075 mol

CuSO₄ : Al₂ (SO₄)₃

3 : 1

0.02 : 1/3×0.02=0.007 mol

CuSO₄ : Cu

3 : 3

0.02 : 0.02

Less number of moles of reactants are produced by CuSO₄ thus it will act as limiting reactant.

4 0

3 years ago