a car traveling at 15m/s slows down at a constant rate of 5 seconds until it stops. what is the acceleration

What does si stand for,when referring to a system of measurement

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?

If an electric circuit is not grounded it is best to reach out and touch it to provide the ground a.true or b.false