The impact of a 100 meter asteroid could kill many people if it struck a major city. Suppose the probability of such an impact in any single year is 1 in 1,000, and suppose we know (somehow) that it has been 1200 years since the last impact
What would that tell us?
A) The prediction must be wrong, since the time since the last impact has been 1200 years.
B) Nothing, we would still presume that the chance of such an impact during the next year is 1 in 1000.
C) We are overdue for such an impact, so we should expect to be hit by something even larger during the next few years.
D) We are now due for such an impact, so the actual probability for the coming year must be much higher than 1 in 1000.
B
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If we double only the mass of a vibrating ideal mass-and-spring system, the mechanical energy of the system
A) increases by a factor of . B) increases by a factor of 2. C) increases by a factor of 3. D) increases by a factor of 4. E) does not change.
The fact that gasoline overflows a full tank on a hot day is evidence that
A) gasoline expands more with increasing temperature than its tank. B) the tank contracts while gasoline expands with temperature. C) both of these D) neither of these
In the context of various observations made, which of the following statements is true of gamma-ray bursts?
A) They occur from one particular region in the sky. B) They glow brightly and resemble novae. C) Relatively long gamma-ray bursts are produced by a kind of supernova explosion. D) Beams of intense radiation flowing into a star result in powerful gamma-ray bursts.
Using the approximate formula for the Doppler shift, 
one finds that a source is moving away at 0.60 c. What result would the exact formula yield for the recession speed?
A. 0.84 c B. 0.72 c C. 0.60 c D. 0.54 c E. 0.40 c