Quando é verão no hemisfério norte, a Terra encontra-se mais perto do Sol?

The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 1013 rad/s. the mass of a nickel atom is 9.75 × 10-26 kg. what is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10-34 j • s, , 1 ev = 1.60 × 10-19 j)

The field lines around one end of a bar magnet are shown below based on the diagram, what can you conclude about the pole of the magnet? a. is a south pole because the field hnes spread out from this end b. a north pole because the field lines spread out from this end c. a nouth pole because the field lines enter the magnet at this end d. is a north pole because the field lines enter the magnet at this end

Which statements did both aristotle and ptolemy assume? check all that apply.