Astudent, along with her backpack on the floor next to her, are in an elevator that is accelerating upward with acceleration a. the student gives her backpack a quick kick at t = 0, imparting to it speed v and causing it to slide across the elevator floor. at time t, the backpack hits the opposite wall a distance l away from the student. find the coefficient of kinetic friction μk between the backpack and the elevator floor. (use any variable or symbol stated above along with the following as necessary: g.)

Assume that two of the electrons at the negative terminal have attached themselves to a nearby neutral atom. there is now a negative ion with a charge -2e at this terminal. what are the electric potential and electric potential energy of the negative ion relative to the electron? the electric potential and the electric potential energy are both twice as much. the electric potential is twice as much and the electric potential energy is the same. the electric potential is the same and the electric potential energy is twice as much. the electric potential and the electric potential energy are both the same. the electric potential is the same and the electric potential energy is increased by the mass ratio of the oxygen ion to the electron. the electric potential is twice as much and the electric potential energy is increased by the mass ratio of the oxygen ion to the electron.