<span>Changes in the forms of energy are called "Energy Conversions"
Hope this helps!</span>
Answer:
The electrostatic force is the force that exists between electrically charged particles or objects at rest.
Ball is projected upwards with speed 20 m/s
now using kinematics

here when ball returns back to same position.
total displacement of ball will be zero.


So ball will return to initial position with same speed in opposite direction.
Answer: How much gravitational potential energy does the ball have at this point? At h = 20.4 m the gravitational potential energy of the ball reaches maximum.
How much work did I do lifting up the ball? As you are lifting the object you are doing work on the object. The work W done on an object by a constant force is defined as W = F·d. It is equal to the magnitude of the force, multiplied by the distance the object moves in the direction of the force.