-1- was created in the 1600 by william gilbert
-2-When the charge is positive, electrons in the metal of the electroscope are attracted to the charge and move upward out of the leaves. This results in the leaves to have a temporary positive charge and because like charges repel, the leaves separate. When the charge is removed, the electrons return to their original positions and the leaves relax
3-
An electroscope is made up of a metal detector knob on top which is connected to a pair of metal leaves hanging from the bottom of the connecting rod. When no charge is present the metals leaves hang loosely downward. But, when an object with a charge is brought near an electroscope, one of the two things can happen.
To solve this problem we will apply the concepts related to the balance of forces. We will decompose the forces in the vertical and horizontal sense, and at the same time, we will perform summation of torques to eliminate some variables and obtain a system of equations that allow us to obtain the angle.
The forces in the vertical direction would be,



The forces in the horizontal direction would be,



The sum of Torques at equilibrium,




The maximum friction force would be equivalent to the coefficient of friction by the person, but at the same time to the expression previously found, therefore


Replacing,


Therefore the minimum angle that the person can reach is 46.9°
Answer:
I assume the higher notes would make the rice vibrate more easily, so a flute.
Electrical generator which operates using a magnetic field. It is the beginning of modern dynamos.