Ninety percent of all normal stars in a Hertzsprung-Russell (H-R) diagram are:
A) in the giant region.
B) in the supergiant region.
C) on the random sequence.
D) on the main sequence.
D
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The lifetime of a ?+ meson normally is 18 nanoseconds. In a large particle accelerator, scientists can create ?+ mesons moving at speeds close to the speed of light. What do the scientists observe when they measure the lifetime of a ?+ meson that is created at high speed?
A) The ?+ meson lasts much more than 18 nanoseconds. B) The ?+ meson lasts 18 nanoseconds. C) The ?+ meson lasts much less than 18 nanoseconds. D) The ?+ meson no longer decays and remains as a stable particle.
States that observers cannot detect their uniform motion through space through internal tests
The diagram below shows five cylinders, each cylinder rotating with constant angular velocity about its central axis. The magnitude of the tangential speed of one point of each cylinder is shown, along with each cylinder's radius and mass. Which cylinder has the largest angular momentum?
A.
B.
C.
D.
E.
What is the approximate surface temperature of a B star?
A) 8,000 K B) 6,000 K C) 20,000 K D) 40,000 K