Q1. how does friction affect the mechanical energy of a system? q 2. a roller coaster is at the stop of a hill and rolls to the top of a lower hill. if mechanical energy is constant, then on the top of which hill is the kinetic energy from the roller coaster motion greater?

Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?