Draw a free-body diagram representing each of the following objects. use the correct force labels:
a. a ball falling in the presence of air resistance
b. a helicopter lifting vertically off a landing pad, not in contact with the ground
c. an athlete running along a horizontal track

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?