HELP ASAP TIMER Three trains are all are moving along a track with the same speed and slam on their brakes. If all three trains have identical coefficients of kinetic friction with the rail surface, which train travels the longest distance to come to a stop?

a
This cannot be determined, without knowing the normal force on the train by the rail.
b
The most massive train.
c
They all travel the same distance in stopping.
d
The least massive train.

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

What is the most useful equation for electric power?

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?