Why does the uv from the sun hurt our eyes. plz

Ultraviolet radiation from the sun is controlled by the ozone but if it infiltrates into the atmosphere it becomes a hazard. The uv reaches our eyes and darkens the retina and blurs vision. The fovea becomes insensitive and the cells dormant. This causes gradual blindness.

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.