Answer:It increases confidence because the more times you conduct the same experiment over and over should either prove your hypothesis right and wrong and eliminate any random occurrences that might affect your results.
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Explanation:
Answer:
(B) Dark energy does not exist and there is much more matter than current evidence suggests.
Explanation:
The repulsive force which is accelerating expansion of the universe is called as dark energy. Most of matter present in the universe is the dark matter of about eighty five percent.
So, a collapsing universe would not have the dark energy and there is more matter which is not the dark matter. This theory is rejected because expansion of the universe is observable.
Answer:
The pressure at point 2 is ![P_2 = 254.01 kPa](https://tex.z-dn.net/?f=P_2%20%20%3D%20254.01%20kPa)
Explanation:
From the question we are told that
The speed at point 1 is ![v_1 = 3.57 \ m/s](https://tex.z-dn.net/?f=v_1%20%20%3D%20%203.57%20%5C%20m%2Fs)
The gauge pressure at point 1 is ![P_1 = 68.7kPa = 68.7*10^{3}\ Pa](https://tex.z-dn.net/?f=P_1%20%20%3D%20%2068.7kPa%20%3D%20%2068.7%2A10%5E%7B3%7D%5C%20%20Pa)
The density of water is ![\rho = 1000 \ kg/m^3](https://tex.z-dn.net/?f=%5Crho%20%20%3D%201000%20%5C%20kg%2Fm%5E3)
Let the height at point 1 be
then the height at point two will be
![h_2 = h_1 - 18.5](https://tex.z-dn.net/?f=h_2%20%20%3D%20%20h_1%20%20-%20%2018.5)
Let the diameter at point 1 be
then the diameter at point two will be
![d_2 = 2 * d_1](https://tex.z-dn.net/?f=d_2%20%20%3D%20%202%20%2A%20d_1)
Now the continuity equation is mathematically represented as
![A_1 v_1 = A_2 v_2](https://tex.z-dn.net/?f=A_1%20v_1%20%20%3D%20%20A_2%20v_2)
Here
are the area at point 1 and 2
Now given that the are is directly proportional to the square of the diameter [i.e
]
which can represent as
![A \ \ \alpha \ \ d^2](https://tex.z-dn.net/?f=A%20%5C%20%5C%20%20%5Calpha%20%5C%20%5C%20%20d%5E2)
=> ![A = c d^2](https://tex.z-dn.net/?f=A%20%3D%20c%20%20%20d%5E2)
where c is a constant
so ![\frac{A_1}{d_1^2} = \frac{A_2}{d_2^2}](https://tex.z-dn.net/?f=%5Cfrac%7BA_1%7D%7Bd_1%5E2%7D%20%20%3D%20%20%5Cfrac%7BA_2%7D%7Bd_2%5E2%7D)
=> ![\frac{A_1}{d_1^2} = \frac{A_2}{4d_1^2}](https://tex.z-dn.net/?f=%5Cfrac%7BA_1%7D%7Bd_1%5E2%7D%20%20%3D%20%20%5Cfrac%7BA_2%7D%7B4d_1%5E2%7D)
=> ![A_2 = 4 A_1](https://tex.z-dn.net/?f=A_2%20%20%3D%20%204%20A_1)
Now from the continuity equation
=>
=>
![v_2 = 0.893 \ m/s](https://tex.z-dn.net/?f=v_2%20%20%3D%20%200.893%20%5C%20%20m%2Fs)
Generally the Bernoulli equation is mathematically represented as
![P_1 + \frac{1}{2} \rho v_1^2 + \rho * g * h_1 = P_2 + \frac{1}{2} \rho v_2^2 + \rho * g * h_2](https://tex.z-dn.net/?f=P_1%20%2B%20%5Cfrac%7B1%7D%7B2%7D%20%20%5Crho%20v_1%5E2%20%2B%20%20%5Crho%20%2A%20%20g%20%2A%20h_1%20%20%3D%20%20P_2%20%2B%20%5Cfrac%7B1%7D%7B2%7D%20%20%5Crho%20v_2%5E2%20%2B%20%20%5Crho%20%2A%20%20g%20%2A%20h_2)
So
=> ![P_2 = \rho * g (h_1 -(h_1 -18.3) + P_1 + \frac{1}{2} * \rho (v_1^2 -v_2 ^2 )](https://tex.z-dn.net/?f=P_2%20%20%3D%20%20%5Crho%20%20%2A%20g%20%20%28h_1%20-%28h_1%20-18.3%29%20%20%2B%20P_1%20%20%2B%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%2A%20%20%5Crho%20%28v_1%5E2%20-v_2%20%5E2%20%29)
substituting values
![P_2 = 1000 * 9.8 (18.3) )+ 68.7*10^{3} + \frac{1}{2} * 1000 ((3.57)^2 -0.893 ^2 )](https://tex.z-dn.net/?f=P_2%20%20%3D%20%201000%20%20%2A%209.8%20%20%2818.3%29%20%29%2B%2068.7%2A10%5E%7B3%7D%20%20%2B%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%2A%20%201000%20%28%283.57%29%5E2%20-0.893%20%5E2%20%29)
![P_2 = 254.01 kPa](https://tex.z-dn.net/?f=P_2%20%20%3D%20254.01%20kPa)
Explanation:
A simple way to state Newton's first law is:
For every action force, there is a reaction force which is equal in magnitude and opposite in direction.