Answer:
Zero or +2
Explanation:
The noble gases already have a avplete outermost shell. They are the least reactive elements of earth?
Their normal oxidation number is zero but some have been shown to be reactive.
They almost entirely reside within galaxies because quasars are a subset of blackholes with a large and fast enough accretion disk to generate a beam of interstellar material perpendicular to itself. This typically only occurs in the largest black holes at the center of galaxies (supermassive blackholes) or at least stellar black holes---which still occur within galaxies because the material is necessary to form them.
Answer: The force constant k is 10600 kg/s^2
Step by step:
Use the law of energy conservation. When the elevator hits the spring, it has a certain kinetic and a potential energy. When the elevator reaches the point of still stand the kinetic and potential energies have been transformed to work performed by the elevator in the form of friction (brake clamp) and loading the spring.
Let us define the vertical height axis as having two points: h=2m at the point of elevator hitting the spring, and h=0m at the point of stopping.
The total energy at the point h=2m is:

The total energy at the point h=0m is:

The two Energy values are to be equal (by law of energy conservation), which allows us to determine the only unknown, namely the force constant k:

Answer:

Explanation:
We can assume this problem as two concentric spherical metals with opposite charges.
We have also to take into account the formulas for the electric field and the capacitance. Hence we have

Where k is the Coulomb's constant. Furthermore, by taking into account the expression for the potential and by integrating
![dV=Edr\\\\V=\int_{R_1}^{R_2}Edr=-\int_{R_1}^{R_2}\frac{kQ}{r^2}dr\\\\V=kQ[\frac{1}{R_2}-\frac{1}{R_1}]](https://tex.z-dn.net/?f=dV%3DEdr%5C%5C%5C%5CV%3D%5Cint_%7BR_1%7D%5E%7BR_2%7DEdr%3D-%5Cint_%7BR_1%7D%5E%7BR_2%7D%5Cfrac%7BkQ%7D%7Br%5E2%7Ddr%5C%5C%5C%5CV%3DkQ%5B%5Cfrac%7B1%7D%7BR_2%7D-%5Cfrac%7B1%7D%7BR_1%7D%5D)
Hence, the capacitance is
![C=\frac{1}{k[\frac{1}{R_2}-\frac{1}{R_1}]}](https://tex.z-dn.net/?f=C%3D%5Cfrac%7B1%7D%7Bk%5B%5Cfrac%7B1%7D%7BR_2%7D-%5Cfrac%7B1%7D%7BR_1%7D%5D%7D)
but R1=a and R2=b

HOPE THIS HELPS!!
It says an object will remain at rest unless external forces act upon it.