In order for a protostar to transition to a full fledge star, what must happen? options: A. Nuclear fusion must occur in the protostar B. Planets must form around the protostar C. The protostar must cool down D. Accretion must occur in the rings around the protostar

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.

Abar magnet cut in half will form a total ofpoles.a)fourb)eightc)two

Astudent weighing 700 n climbs at constant speed to the top of an 8 m vertical rope in 10 s. the average power expended by the student to overcome gravity is most nearly