The answer is A. The kinetic energy
20N•m or 20J. Work is equal to force•distance, and 5N•4m is 20N•m, or J
Answer:
Elastic potential energy, 
Explanation:
Charge, 
Potential, V = 50 V
It is required to find the electric potential energy in a capacitor stored in it. The formula of the electric potential energy in a capacitor is given by :

So, the electric potential energy stored in the capacitor is 
An electric generator is when a magnet is rotated through a coil of wire to produce an electric current.
Answer:

where E = electric field intensity
Explanation:
As we know that plastic ball is suspended by a string which makes 30 degree angle with the vertical
So here force due to electrostatic force on the charged ball is in horizontal direction along the direction of electric field
while weight of the ball is vertically downwards
so here we have


since string makes 30 degree angle with the vertical so we will have





where E = electric field intensity