Which of the following situations would produce an average velocity of zero? o a. a horse galloping in a field b. a round-trip to school and back o c. a trip, first to the moon, then onto mars o d. the criss-crossing path of a flying bug

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

=force × distance a. work b. velocity c. pressure d. momentum

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.