A 3.0-kg cart rolls down a hill. Assume that the height of the cart changes from a maximum of 4.0 meters at the top of the hill to 0.0 meters at the bottom. The speed of the cart changes from 0.0 m/s to 3.0 m/s. How much kinetic energy does the cart have when it is half-way down the hill?
A) 6.0J
B) 12.0J
C) 58.8J
D) 117.6J

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?