Astar has a mass of 1.36 x 1030 kg and is moving in a circular orbit about the center of its galaxy. the radius of the orbit is 2.1 x 104 light-years (1 light-year = 9.5 x 1015 m), and the angular speed of the star is 1.1 x 10-15 rad/s. (a) determine the tangential speed of the star. (b) what is the magnitude of the net force that acts on the star to keep it moving around the center of the galaxy?

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?