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IgorLugansk [536]
2 years ago
13

750 million years ago, there was enough Uranium-235 present in Oklo, Gabon to have a natural fission reactor occur and generate

a chain reaction. If there is currently 50kg of U-235 present in Oklo, how much must have been present 750 million years ago when the reaction took place?
Physics
2 answers:
Komok [63]2 years ago
3 0
<span>With a half-life of 700 million years, U-235 would have had twice as much mass at a time 700 MYA. This would have put the mass at 100kg at that time. Going back another 50 million years would be (50/700) or 1/14 of the half-life, or (1/2 * 1/14), or 1/28 of the total mass. 1/28 of 100kg is 3.57kg, so the amount present at the 750MYA mark would be approximately 103.57kg of U-235.</span>
tiny-mole [99]2 years ago
3 0

Answer

B

Explanation: i had that same question

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Suppose we were to attempt to use a similar machine to measure the charge-to-mass ratio of protons, instead. Suppose, for simpli
Igoryamba

Answer:

In summary, the biggest difference in the experiment is that the proton mass is much more than the electron mass, so the voltages used are high and very dangerous.

Explanation:

The machine to measure the ratio of charge / mass of the electron, has two parts: a part where it accelerates the electrons in an electric field and a second section to charter the beam and measure its radius of curvature calculated from here the q / m ratio

In the case of having protons, the charge has the same value as that of the electrons, but with a positive charge, so the polarities of the fields should be changed.

The mass of the protons is much greater than the mass of the electrons, which introduced a significant difference in the excrement, since similar electric fields the speed of the protons is much less than the speed of the electrons, so the magnetic field through which the voters pass to have equivalent deflations in many cases this small values ​​of the magnetic field are not desirable due to the interference of the Earth's magnetic field.

Another solution could be to increase the electric field to have the protons with speeds similar to the electors, this possibility is not easy either, because the field of trunking of more than 5000 V would be needed, which are very dangerous.

In summary, the biggest difference in the experiment is that the proton mass is much more than the electron mass, so the voltages used are high and very dangerous.

3 0
2 years ago
The gas tank of Dave’s car has a capacity of 12 gallons. The tank was 38 full before Dave filled it to capacity. It cost him $2.
m_a_m_a [10]

Answer:

$ 18.75            

Explanation:

given,                                              

capacity of the Dave’s car = 12 gallons

Assuming that the tank is 3/8 full before

Cost of gas per gallon =  $2.50 per gallon of gas

Volume Dave have to fill                      

       =1 - \dfrac{3}{8}                          

       =\dfrac{5}{8} of full tank              

       =\dfrac{5}{8}\times 12              

volume Dave have to fill = 7.5 gallons          

total money Dave spent                  

     = 7.5 gallons x $2.50                

     = $ 18.75                                            

Dave have to spend $ 18.75 to fill tank to it capacity.

5 0
2 years ago
Read 2 more answers
Which statement would be a valid argument in favor of using nuclear power? There are few negative impacts from mining the fuel.
fgiga [73]
Okay so, lets use the process of elimination here. 

<span>A)There are few negative impacts from mining the fuel.
B)Reactors are safe from natural disasters.
C)There are little to no waste products from fission.
D)Nuclear power does not contribute greenhouse gases.

First off, we know B cannot be correct, seeing as how reactors are fragile and are damaged easily by Japan's earthquakes. So we can eliminate B from the choices. We then can eliminate C, since fission creates high levels of nuclear waste, so that leaves us with just A, and D. We can then eliminate A since uranium is radioactive, there is always a chance for negative effects.

So, the correct answer is D</span>
6 0
2 years ago
Read 2 more answers
A uniform cylindrical steel wire (density: 7.8 x 103 kg/m3), 58.0 cm long and 1.34 mm in diameter, is fixed at both ends. To wha
lbvjy [14]

Answer:

T= 354.65 N

Explanation:

Given that

ρ= 7800 kg/m³

L= 58 cm

d=1.34 mm

f= 311 Hz

T= Tension

Speed of wave ,V

V = f λ      

V = f L

V= 311 x 0.58 m/s

V=180.38 m/s

Area of cross sectional

A= πr² mm²

A= 3.14 x 0.67² mm²

A=1.41 mm²

Mass = Density x Volume

m=7800\times 1.41\times 10^{-6}\ kg/m

m=0.0109 kg/m

Tension ,T

T=m V^2

T= 0.0109 x 180.38² N

T= 354.65 N

     

3 0
2 years ago
Eratosthenes determined the circumference of Earth by conducting an experiment. Put his steps in order as they correlate to the
galben [10]

Solution: The correct order is: C, A, B

The statement of the problem:

How can we prove Earth is round and calculate its circumference?

Hypotheis:

If the sun casts shadows at different angles at the same time of day in different places, we can determine how much Earth curves.

If the Earth was flat, the angle measured at different places at the same time of the day would be same.

Observation:

In Syene, the sun's rays are vertical at noon. At the same time in Alexandria, the rays are 7.2 degrees from the vertical.

5 0
2 years ago
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