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3 years ago

Use your periodic table to answer the following question.

Physics

1 answer:

Pavel [41]3 years ago

6 0

Helium has only 2 electrons in it's valence shell

So, option D is your answer.

Hope this helps!

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A planet in elliptical orbit around a star moves from the point in its orbit furthest from the star (A) to the closest point (P)

Virty [35]

Answer:

Zero work done,since the body isn't acting against or by gravity.

Explanation:

Gravitational force is usually considered as work done against gravity (-ve) and work by gravity ( +ve ) and also When work isn't done by or against gravity work done in this case is zero.

Gravitational force can be define as that force that attracts a body to any other phyical body or system that have mass.

The planet been considered as our system in this case is assumed to have mass, and ought to demonstrate such properties associated with gravitational force in such system. Such properties include the return of every object been thrown up as a result of gravity acting downwards. The orbiting nature of object along an elliptical part when gravitational force isn't acting on the body and it is assumed to be zero.

6 0

3 years ago

A 20-kg barrel is rolled up a 20-m ramp to the back of a truck whose floor is 5.0 m above the ground. What work is done in loadi

oee [108]

The angle of inclination is calculated using sin function,

sin θ = 5 m / 20 m = 0.25

θ = 14.4775°

The net force exerted is then calculated:
F net = m g sin θ = 20 * 9.8 * 0.25

F net = 49N

Work is product of net force and distance:
W = F net * d = 49 * 20

Work = 980 J

4 0

3 years ago

The ratio of carbon-14 to nitrogen-14 is an artifact is 1:3. Given that half-life of carbon-14 is 5730years, how old is the arti

dusya [7]

Answer:

9155 years old

Explanation:

We use the following expression for the decay of a substance:

$N = N_0\,\,e^{-k*t}$

So we first estimate the value of k knowing that the half-life of the C14 is 5730 years:

$N = N_0\,\,e^{-k*t}\\N_0/2=N_0\,\,e^{-k*5730}\\1/2 = e^{-k*5730}\\ln(1/2)=-k*5730\\k= 0.00012$

so, now we can estimate the age of the artifact by solving for"t" in the equation:

$1/3=e^{-0.00012*t}\\ln(1/3)= -0.00012*t\\t=9155. 102$

which we can round to 9155 years old.

5 0

3 years ago

Potassium is a crucial element for the healthy operation of the human

Degger [83]

Answer:

The mass of the Potassium-40 is $m_{40}} = 2.88*10^{-6} kg$

The Dose per year in Sieverts is $Dose_s = 26.4 *10^{-10}$

Explanation:

From the question we are told that

The isotopes of potassium in the body are Potassium-39, Potassium-40, and Potassium- 41

Their abundance is 93.26%, 0.012% and 6.728%

The mass of potassium contained in human body is $m = 3.0 g = \frac{3}{1000} = 0.0003 \ kg$ per kg of the body

The mass of the first body is $m_1 = 80 \ kg$

Now the mass of potassium in this body is mathematically evaluated as

$m_p = m * m_1$

substituting value

$m_p = 80 * 0.0003$

$m_p =0.024 kg$

The amount of Potassium-40 present is mathematically evaluated as

$m_{40}} =$ 0.012% * 0.024

$m_{40}} = \frac{0.012}{100} * 0.024$

$m_{40}} = 2.88*10^{-6} kg$

The dose of energy absorbed per year is mathematically represented as

$Dose = \frac{E}{m_1}$

Where E is the energy absorbed which is given as $E = 1.10 MeV = 1.10 * 10^6 * 1.602*10^{-19}$

Substituting value

$Dose = \frac{ 1.10 * 10^6 * 1.602*10^{-19}}{80}$

$Dose = 22*10^{-10} J/kg$

The Dose in Sieverts is evaluated as

$Dose_s = REB * Dose$

$Dose_s = 1.2 * 22*10^{-10}$

$Dose_s = 26.4 *10^{-10}$

3 0

3 years ago

What property is a characteristic of a pure substance that can be observed with out changing the substance into something else

WARRIOR [948]

physical property is a characteristics of a pure substance that can be observed without changing the substance into someone else.

4 0

3 years ago