Answer: a) Cnew=Cinitial ; b) λouter new= 2*λ outer initial
Explanation: In order to explain this question we have to take into account the expression of teh cylinder capacitor given by:
C/L= (2*π*εo)/ln (b/a)= where b and a are the outer and inner radius, respectively. L is the length of the capacitor.
As you can se this formule depents of geometrical characateristics of the capacitor.
The capacitance is the same after change the densities of charge.
On the other hand,
The new charge in each cylinder ( inner and outer) is determined
The new potential is 2 times the initial one so
V new= 2* Vinitial
Also we know that
Vnew= Q/C= λnew*L/C; C= constant
using this formule and considering that V new is doubled then the charge per one meter length, is also doubled .
This is as follow:
Vnew= λnew*L/C=
λnew = (2*Vinitial)* C/L= 2 (λ initial)
Then λouter new = 2* λouter initial
Answer:
The radius of the sphere is 4.05 m
Explanation:
Given;
potential at surface,
= 450 V
potential at radial distance,
= 150
radial distance, l = 8.1 m
Apply Coulomb's law of electrostatic force;


Therefore, the radius of the sphere is 4.05 m
You have to be 90 m away from the cat
Just divide 90 by 17.4 and you will get - 5.172 seconds
- It will take 5.17 seconds to accelerate uniformly to stop in exactly 2 m before the cat
Answer:

Explanation:
k = spring constant of the spring = 40 Nm⁻¹
A = amplitude of the simple harmonic motion = 4 cm = 0.04 m
m = mass of the block attached to spring = 0.20 kg
w = angular frequency of the simple harmonic motion
Angular frequency of the simple harmonic motion is given as 
= Speed of the block as it pass the equilibrium point
Speed of the block as it pass the equilibrium point is given as

The third one looks correct to me