Answer:
The relationship between the initial stored energy 
and the stored energy after the dielectric is inserted 
is:
c) 
Explanation:
A parallel plate capacitor with 
that is connected to a voltage source 
holds a charge of 
. Then we disconnect the voltage source and keep the charge 
constant . If we insert a dielectric of 
between the plates while we keep the charge constant, we found that the potential decreases as:
The capacitance is modified as:
The stored energy without the dielectric is
The stored energy after the dielectric is inserted is:
If we replace in the above equation the values of V and C we get that
Finally
Answer:
Explanation:
Moment of inertia of a disc = 1/2 M R²
Since mass is same for both and radius are r and 2r, their moment of inertia can be in the ratio of 1: 4 . Let them be I and 4I . Angular speed are ω₀ and - ω₀ .
We shall apply law of conservation of angular momentum .
initial total angular momentum
I x ω₀ - 4I x ω₀ = - 3Iω₀
Let final common angular momentum be ω
total final angular momentum = ( I + 4I ) ω
Applying law of conservation of angular momentum
( I + 4I ) ω = - 3Iω₀
ω = - 3 / 5 ω₀ .
b )
Initial total rotational K E
= 1/2 I ω₀² + 1/2 4I ω₀²
= 1/2 x5I ω₀²
Final total rotational K E
= 1/2 ( I + 4I ) ( - 3 / 5 ω₀ )²
= 1/2 x 9 / 5 I ω₀²
= 9 / 10I ω₀²
change in rotational kinetic energy = 9 / 10I ω₀² - 1/2 x5I ω₀²
(9/10 - 5/2) xI ω₀²
=( .9 - 2.5 )I ω₀²
= - 1.6 I ω₀² Ans
Answer:
volume
Explanation:
it depends on the volume of the items
hope this helps
Using the rotational equivalent of force:
Which is T = I*Alpha
Where: T is torque, I is the moment of inertia and Alpha is
the angular acceleration.
This is for the flywheel: J = 1/2mr^2 = 5*3^2 = 45
kgm^2
From the equation:
T = J*dω/dt
we get:
Δt = J*Δω/T = 45*8.13/110.0 = 3.326 sec
S = frequency * wavelength
s = 100 * 0.30
s = 30 Hz
hope this helps :)
