Jalyn ran at speed of 3 m/s then came to a sudden stop during a time period of 3 s. What was his acceleration? show all your work

If 21.2 kcals of energy is released by this reaction, how many kj does the reaction release? (1 cal 4.184 j)

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?

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in