Why does the sun produce energy

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Will mark as brainliest how does a catapult increase the trajectory of an object? ps. answer as if u were a 5th grader

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?