The age of stars in a cluster can be determined by
A) finding spectroscopic binaries in the cluster.
B) determining the main sequence turnoff point.
C) finding pulsating variable stars in the cluster.
D) counting the number of stars in each spectral class.
E) fitting the position of the main sequence to the Sun.
B
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Mass on a Spring: An object attached to an ideal spring executes simple harmonic motion. If you want to double its total energy, you could
A. double the amplitude of vibration. B. double the force constant (spring constant) of the spring. C. double both the amplitude and force constant (spring constant). D. double the mass. E. double both the mass and amplitude of vibration.
A series of possible particle processes are listed below. Which (if any) are probably not processes mediated by the weak interaction? (Note: ? = a photon, ? = a muon, which is a lepton like the electron but heavier. Don’t worry about conservation of energy.)
A. 
B. 
C. 
D. 
E. All might be weak processes.
Indicate the validity of the following decay processes. For any reactions which are not valid (that is, not permitted), give a reason. (a) ?0 —> ?0 + ?0 (b) ?? —> ?? + ?? (c) ?0 —> ?0 + ?0 + ?+
The Appalachian Mountains in the eastern United States are examples of ______________ mountains
Fill in the blank(s) with correct word