A 15.0kg box slides down an incline 5.00 m high and 9.00 m long. It starts at rest at the top and moves at the speed 2.50m/s when it is at the bottom. How much work is done by friction? [688J].
What is the energy transformation efficiency? [94%]

Which situation will produce the greatest change of momentum

In a good thermo flask the main cause of heat loss is

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?