Answer:
The spring force constant is
.
Explanation:
We are told the mass of the ball is
, the height above the spring where the ball is dropped is
, the length the ball compresses the spring is
and the acceleration of gravity is
.
We will consider the initial moment to be when the ball is dropped and the final moment to be when the ball stops, compressing the spring. We supose that there is no friction so the initial mechanical energy
is equal to the final mechanical energy
:

Initially there is only gravitational potential energy because the force of the spring isn't present and the speed is zero. In the final moment there is only elastic potential energy because the height is zero and the ball has stopped. So we have that:

If we manipulate the equation we have that:




Answer:
a) E = 0
b) 
Explanation:
The electric field for all points outside the spherical shell is given as follows;
a) 
From which we have;

E = 0/A = 0
E = 0
b) 


By Gauss theorem, we have;

Therefore, we get;

The electrical field outside the spherical shell


Therefore, we have;

Answer:
doubled the initial value
Explanation:
Let the area of plates be A and the separation between them is d.
Let V be the potential difference of the battery.
The energy stored in the capacitor is given by
U = Q^2/2C ...(1)
Now the battery is disconnected, it means the charge is constant.
the separation between the plates is doubled.
The capacitance of the parallel plate capacitor is inversely proportional to the distance between the plates.
C' = C/2
the new energy stored
U' = Q^2 / 2C'
U' = Q^2/C = 2 U
The energy stored in the capacitor is doubled the initial amount.
Hello There!
It's a Property of matter where atoms in an object are aligned into domains