Answer:
position, speed, direction, and acceleration.
Explanation:
Refractive Index is a ratio of two similar physical quantity which is dimension less
refractive index = sin I / sin r
therefore it doesn't have a unit.
<span>Hello,
The answer is:
A vibrating tuning fork is struck and begins to vibrate as the object used to strike it is placed away from the tuning fork.</span>
To develop this problem it is necessary to apply the concepts related to the calculation of the Force through density and volume as well as the ideal gas law.
By definition, force can be expelled as
F = ma
Where,
m = mass
a = Acceleration
At the same time the mass can be defined as function of density and Volume
![m = \rho V](https://tex.z-dn.net/?f=m%20%3D%20%5Crho%20V)
Therefore if we do a sum in the spherical balloon we have,
![\sum F = 0](https://tex.z-dn.net/?f=%5Csum%20F%20%3D%200)
![F_w +F_h-F_b=0](https://tex.z-dn.net/?f=F_w%20%2BF_h-F_b%3D0)
Where,
= Force by weight of balloon
= Force by weight of helium gas
= Buoyant force
![mg + V \rho g - V\rho_a g = 0](https://tex.z-dn.net/?f=mg%20%2B%20V%20%5Crho%20g%20-%20V%5Crho_a%20g%20%3D%200)
Re-arrange to find ![\rho,](https://tex.z-dn.net/?f=%5Crho%2C)
![\rho = \rho_a - \frac{m}{V}](https://tex.z-dn.net/?f=%5Crho%20%3D%20%5Crho_a%20-%20%5Cfrac%7Bm%7D%7BV%7D)
Our values are given as,
![r= 1.55m](https://tex.z-dn.net/?f=r%3D%201.55m)
![V = \frac{4}{3} \pi r^3](https://tex.z-dn.net/?f=V%20%3D%20%5Cfrac%7B4%7D%7B3%7D%20%5Cpi%20r%5E3)
![V = \frac{4}{3} \pi (1.55)^3](https://tex.z-dn.net/?f=V%20%3D%20%5Cfrac%7B4%7D%7B3%7D%20%5Cpi%20%281.55%29%5E3)
![V = 15.59m^3](https://tex.z-dn.net/?f=V%20%3D%2015.59m%5E3)
Replacing the values we have,
![\rho = 1.19kg/m^3 - \frac{2.7}{15.59}](https://tex.z-dn.net/?f=%5Crho%20%3D%201.19kg%2Fm%5E3%20-%20%5Cfrac%7B2.7%7D%7B15.59%7D)
![\rho = 1.0168kg/m^3](https://tex.z-dn.net/?f=%5Crho%20%3D%201.0168kg%2Fm%5E3)
Applying the ideal gas law we have finally that
![P = \frac{\rho}{M_0} RT](https://tex.z-dn.net/?f=P%20%3D%20%5Cfrac%7B%5Crho%7D%7BM_0%7D%20RT)
Where,
P = Pressure
Density
M_0 Molar mass (0.004Kg/mol for helium)
R= Gas constant
T = Temperature
Substituting
![P = \frac{1.0168}{0.004} *8.314*290](https://tex.z-dn.net/?f=P%20%3D%20%5Cfrac%7B1.0168%7D%7B0.004%7D%20%2A8.314%2A290)
![P = 612891.452Pa](https://tex.z-dn.net/?f=P%20%3D%20612891.452Pa)
![P = 0.613Mpa](https://tex.z-dn.net/?f=P%20%3D%200.613Mpa)
Therefore the absolute pressure of the helium gas is ![0.613Mpa](https://tex.z-dn.net/?f=0.613Mpa)
1. Mass number of Lithium-7: 7
Explanation:
- The atomic number of an element is equal to the number of protons inside its nucleus
- The mass number of an element is equal to the number of protons+neutrons inside its nucleus
The nomenclature "Element-X", where X is the number of protons+neutrons, is used to indicate the mass number of the isotope. Therefore, an isotope of LIthium-7 has a mass number of 7.
2. An isotope of lithium-8 contains 5 neutrons
Explanation:
Lithium is the third element of the periodic table, so its atomic number is 3, which means that it has 3 protons.
In this problem, we have an isotope of lithium-8, which means that it has a mass number of 8: so, the sum of neutrons+protons in its nucleus is 8:
![p+n=8](https://tex.z-dn.net/?f=p%2Bn%3D8)
where p is the number of protons and n the number of neutrons. However, we also know that for lithium p=3, so we can find the number of neutrons:
![n=8-p=8-3=5](https://tex.z-dn.net/?f=n%3D8-p%3D8-3%3D5)