The tape in a videotape cassette has a total length 189 m and can play for 2 h. As the tape
starts to play, the full reel has an outer radius
of 47 mm and an inner radius of 14 mm. At
some point during the play, both reels will
have the same angular speed.
What is this common angular speed?
Answer in units of rad/s.

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.