Amass m is tied to an ideal spring with force constant k and rests on a frictionless surface. the mass moves along the x axis. assume that x=0 corresponds to the relaxed position of the spring. the mass is pulled out to a position xm and released. derive an expression for the positions at which the kinetic energy of the mass is equal to the elastic potential energy of the spring.

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

Carbon 14 is a naturally occurring stable

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?