While watching a star, you see it moves 15 degrees across the sky. How long have you been watching it?
A) 1 hour
B) 3 hours
C) 15 minutes
D) 15 seconds
E) 1 minute
A
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A diver, below the surface of a lake, notices that no light appears to be coming toward her greater than the angle 
measured from the vertical. If the index of refraction of water is 1.33, what is the angle 
A. 
B. 
C. 
D. 
E. 
How can the Doppler method be used to measure the orbital period of a planet?
A) by measuring the speed at which the star orbits the mutual center-of-mass of the star and planet B) by measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak C) by measuring the asymmetries in the velocity curve D) by measuring the amount by which the starlight is reduced when the planet transits
Radon has a 4-day half-life. Starting with 10 radon atoms, how many will remain after 4 days?
A) Precisely five. B) Either four, or five, or six. C) Precisely zero. D) About 5, but this prediction is uncertain due to the inaccuracies of our measuring devices. E) About 5, but this prediction is uncertain due to quantum uncertainties.
An ice skater performs a pirouette (a fast spin) by pulling in his outstretched arms close to his body. What happens to his rotational kinetic energy about the axis of rotation?
A) It changes, but it is impossible to tell which way. B) It increases. C) It does not change. D) It decreases.