Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 




True is the anwser to your question
Hope this helps
To solve this problem we will apply the concepts related to the Electrostatic Force given by Coulomb's law. This force can be mathematically described as

Here
k = Coulomb's Constant
Charge of each object
d = Distance
Our values are given as,


d = 1 m
a) The electric force on charge
is


Force is positive i.e. repulsive
b) As the force exerted on
will be equal to that act on
,


Force is positive i.e. repulsive
c) If
, a negative sign will be introduced into the expression above i.e.


Force is negative i.e. attractive
Answer:
a)
, b)
, c) 
Explanation:
a) The capacitance of two parallel plates capacitor with dielectric is given by the following expression:

Where:
- Dielectric constant.
- Vaccum permitivity.
- Plate area.
- Distance between plates.
Hence, the capacitance of the system is:



b) The charge can be found by using the definition of capacitance:




c) The energy stored in the charged capacitor is:



