For the Pleiades, a fifty-million-year-old cluster, we find classes ________ and ________ already leaving the main sequence, making the seven bright giants in the "seven sisters."
Fill in the blank(s) with correct word
O; B
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A Carnot cycle, operating as a heat engine, consists, in the order given, of
a. an isothermal expansion, an isothermal compression, an adiabatic expansion and an adiabatic compression. b. an adiabatic expansion, an adiabatic compression, an isothermal expansion and an isothermal compression. c. an isothermal expansion, an adiabatic compression, an isothermal compression and an adiabatic expansion. d. an adiabatic compression, an isothermal compression, an isothermal expansion and an adiabatic expansion. e. an isothermal expansion, an adiabatic expansion, an isothermal compression and an adiabatic compression.
Heisenberg's thought experiment to determine the location of an electron is illustrated here. Why don't we observe the effects of the uncertainty principle in our macroscopic world?
a. The uncertainty principle is turned off in the macroscopic world. b. We never want to know both an object's momentum and its position at the same time. c. Because of the smallness of Planck's constant. d. Because the deBroglie wavelengths of macroscopic objects are too large. e. Because the relativistic principles of Einstein apply instead.
An object is executing simple harmonic motion. What is true about the acceleration of this object? (There may be more than one correct choice.)
A) The acceleration is a maximum when the displacement of the object is a maximum. B) The acceleration is a maximum when the speed of the object is a maximum. C) The acceleration is a maximum when the displacement of the object is zero. D) The acceleration is zero when the speed of the object is a maximum. E) The acceleration is a maximum when the object is instantaneously at rest.