Aball is thrown upward from the ground with an initial speed speed of 25 meters/second; at the same instant, a ball is dropped from rest from a building 15 meters high. after how long will the balls be at the same height?

Patients with brain tumors may elect to have a procedure known as gamma knife. in a typical gamma knife procedure gamma rays are directed toward a tumor with contact to surrounding tissues. limiting contact between gamma rays and healthy tissue is important because