Without the ability to measure, it would be difficult for scientists to conduct experiments or form theories. Not only is measurement important in science and the chemical industry, it is also essential in farming, engineering, construction, manufacturing, commerce, and numerous other occupations and activities.
The electric force acting on the charge is given by the charge multiplied by the electric field intensity:

where in our problem

and

, so the force is

The initial kinetic energy of the particle is zero (because it is at rest), so its final kinetic energy corresponds to the work done by the electric force for a distance of x=4 m:
Her speed was 7.27 meters per second
So??
what is the question??