Which star spends the longest time in the protostellar phase of life?
A) a 1-solar-mass star
B) a 2-solar-mass star
C) a 3-solar-mass star
D) a 4-solar-mass star
E) a 5-solar-mass star
A
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Simple Pendulum: A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves downward with constant acceleration?
A. The period does not change. B. The period increases. C. The period decreases. D. The period becomes zero. E. The period increases if the upward acceleration is more than g/2 but decreases if the upward acceleration is less than g/2.
Refracting Telescope: You have a choice between two lenses of focal lengths fa and fb, where fb = 2fa, to use as the objective lens in building a refracting telescope. If the magnification you obtain using lens a is Ma, what will be the magnification when using lens b?
A. Mb = 2 Ma B. Mb = 4 Ma C. Mb = 8 Ma D. Mb = Ma/4 E. Mb = Ma/2
When a load of wood is thrown overboard from a boat in a swimming pool, the pool level
A) rises. B) falls. C) remains unchanged.
A 2.00-m long piano wire with a mass per unit length of 12.0 g/m is under a tension of 8.00 kN. What is the frequency of the fundamental mode of vibration of this wire?
A) 204 Hz B) 102 Hz C) 408 Hz D) 510 Hz E) 153 Hz