A man weighing 70 kg runs alongside railroad tracks with a velocity of 18 km/h, and jumps into a car of weight 100 kg standing on the tracks. Calculate the velocity with which the car and man will start moving.

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?