A student wants to drag a box of books across the floor to his room, which is 2 m from where he is standing. If he applies a force of 300 N at an angle of 30° to the horizontal, how much force actually does work to move the box?
-150 N
-300 N
-0 N
-260 N

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?

Which law represents the thermodynamic statement of the conservation of energy of a system? a. the fourth law b. the first law c. the second law d. the third law

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight