Answer:
30 cm
Explanation:
From the principle of moment,
when a body is in equilibrium,
Sum of clock wise moment = sum of anti clock wise moment.
Note: That before Doug hangs the last mass, The clock wise moment is greater than the anti close wise moment.
As such the third mass will be placed before the knife edge. As shown in figure 1 on the attached file.
From the diagram,
W₁(50-30) + W₃(x-50) = W₂(80-50)
were, W₁ = m₁g = 0.4×9.8 = 3.92 N ( Where m₁ = 0.4 kg and g = 9.8 m/s²)
W₂ = m₂g =0.6×9.8 = 5.88 N ( where m₂ = 0.6 kg)
W₃ = m₃g = 0.3×9.8 = 2.94 N ( where m₃ = 0.3 kg)
Therefore,
3.92(30) + 2.94(50-x) = 5.88(30)
117.6 + 147-2.94x = 176.4
2.94x+264.6 = 176.4
-2.94x = 176.4-264.6
2.94x = 88.2
x = -88.2/-2.94
x = 30 cm
Thus the third mass must be hung 30 cm
C. Seismic energy
This is energy that is released in earthquakes.
Answer: Option (c) is the correct answer.
Explanation:
Atomic number of hydrogen is 1 and one dot in its lewis structure displays only one electron. So, in order to complete its octet it needs one more electron.
Atomic number of carbon is 6 and its electronic distribution is 2, 4. Carbon needs 4 more electrons in order to complete its octet.
Atomic number of oxygen is 8 and its electronic distribution is 2, 6. In order to complete octet, oxygen needs 2 more electrons.
Atomic number of fluorine is 9 and its electronic distribution is 2, 7. In order to complete octet, fluorine needs 1 more electron.
Hence, we can conclude that out of the given options, lewis dot structure of oxygen atom needs 2 more electrons in its outermost shell.
Answer:
The value is
Explanation:
From the we are told that
The radius of the sphere is
The temperature is
The average temperature of the rest of the universe is
Generally the change in entropy of the entire universe per second is mathematically represented as
Here is the entropy of the rest of the universe which is mathematically represented as
Here Q is the quantity of heat radiated by the star which is mathematically represented as
Here is the Stefan-Boltzmann constant with value
=>
=>
So
=>
Here is the entropy of the rest of the universe which is mathematically represented as
=>
=>
So
=>
Answer:
Explanation:
It's not equal and opposite. You're thinking of Newton's 3rd Law. This is not that. This is gravitational attraction between 2 objects. We can figure out mathematically the pull that the earth has on a single person, by using the equation for gravitational force and the universal gravitational constant, G:
where G is the universal gravitational constant, m1 is the mass of one person, m2 is the mass of the earth, and r-squared is the addition of the radius of the earth plus the radius of you in relation to the surface of the earth.
Let's say a person weighs 150 pounds; in Newtons this is 667 N (rounded from 667.233); his mass then, in terms of the metric system (using 9.8 for gravity), is 68.2 kg. Let's also say that this person is 6 feet tall. 6 feet is the same as 1.83 m (rounded to 3 sig fig's) and the radius from that person's center to the surface of the earth would be about half that height at r = .915 meters. Filling in the formula:
it turns out that the person's radius adds nothing significantly to the radius of the earth, so it doesn't even count mathematically. It's way too small compared to the earth's radius (which is the denominator of that equation). We find that
That's the pull that the earth has on that person which, not coincidentally, is the weight in pounds we said that the person was. Isn't physics amazing!?