Answer:
The mass of the sand that will fall on the disk to decrease the is 0.3375 kg
Explanation:
Moment before = Moment after
where;
I is moment of inertia = Mr² = 0.3 x (0.3)² = 0.027 kg.m²
substitute this in the above equation;
Therefore, the mass of the sand that will fall on the disk to decrease the is 0.3375 kg
When the capacitor is connected to the voltage, a charge Q is stored on its plates. Calling the capacitance of the capacitor in air, the charge Q, the capacitance
and the voltage (
) are related by
(1)
when the source is disconnected the charge Q remains on the capacitor.
When the space between the plates is filled with mica, the capacitance of the capacitor increases by a factor 5.4 (the permittivity of the mica compared to that of the air):
this is the new capacitance. Since the charge Q on the plates remains the same, by using eq. (1) we can find the new voltage across the capacitor:
And since , substituting into the previous equation, we find: