Which physicist first identified the electron as an independent part of the atom?

Thomson conducted a series of experiments on cathode ray tubes, which led him to the discovery of electrons.

This is how on April 30th, 1897 Thomson announced the discovery of the electron (although at that time he called it a corpuscle)

This discovery was considered one of the milestones in science of the late nineteenth century, since it allowed to have a new conception of the structure of matter and its interaction with energy.

It should be noted that from this discovery, Thomson proposed a new model of the atom that although erroneous, remained valid for years and served as the basis for new postulates and research on the subject.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards