Reactive elements, such as alkali metals and halogens, are found in nature only as

Under normal temperature and pressure conditions, what type of rock could be formed from weathering in erosion of metamorphic rock

Abeam of electrons with of wavelength of 7.5 x 10-6 m is incident on a pair of narrow rectangular slits separated by 0.75 mm. the resulting interference pattern is projected onto a screen 10.0 m from the slits. what is the separation of the interference maxima in the resulting interference pattern?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.