A 25 metric ton train moves toward the south at 70 m/s. At what speed must it travel to have three times its original momentum (to 2 sig figs)?

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.

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?

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?