a rocket is continuously firing its engines as it accelerates away from earth. for the first kilometer of its ascent, the mass of fuel ejected is small compared to the mass of the rocket. for this distance, which of the following indicates the changes, if any, in the kinetic energy of the rocket, the gravitational potential energy of the earth-rocket system, and the mechanical energy of the earth-rocket system?

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?