If the N pole of a magnet is brought near to an unmagnetized iron, nail, then the nail becomes​

Need asap ‼️ 20 pts which gravitational force field diagram is drawn correctly? (answers in pictures below)

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?

What is the speed of an object at a given moment?