Aman paddles a canoe in a long, straight section of a river. the canoe moves downstream with constant speed 3 m/s relative to the water. the river has a steady current of 2 m/s relative to the bank. the man's hat falls into the river. four minutes later, he notices that his hat is missing and immediately turns the canoe around, paddling upriver with the same constant speed of 3 m/s relative to the water. how long does it take the man to row back upriver to reclaim his hat?

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?