A spaceship, moving away from the Earth at a speed of 0.9c, shines a green laser backwards at Earth. An observer on Earth would see the light arriving at a speed of
A. c but at a smaller frequency.
B. more than c but less than 1.9c.
C. 1.9c and with a shorter wavelength.
D. c but at a shorter wavelength.
E. 0.1c and with an inverted frequency.
Answer: A
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A) warmer still. B) cooler. C) neither warmer nor cooler.
The iron nucleus has the greatest binding energy of any nucleus
A) True B) False
A ball is thrown horizontally from the top of a building. What will be its vertical displacement from the top of building 2.0 seconds after it leaves your hands?
A) 4.9 m B) 9.8 m C) 19.6 m D) 40.2 m E) 52.4 m
Why do higher mass stars live shorter lives on the main sequence than lower mass stars?
a. Higher mass stars burn through their nuclear fuel faster. b. Lower mass stars don't get their energy from that same nuclear fusion source as higher mass stars. c. Higher mass stars have less hydrogen fuel to burn. d. Lower mass stars spend a longer time evolving to the main-sequence. e. All of the above are false.