Please answer the question in the picture

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

Arock collection comes from which part of earth?

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage