Who proposed a model with the Sun (rather than Earth) at the center of the solar system, which was then tested by the other people listed below?
a. Copernicus
b. Tycho
c. Kepler
d. Galileo
Ans: a. Copernicus
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The star HR 4621 has an apparent magnitude of 2.6 and an absolute magnitude of -0.3 . This star is at a distance
a. closer than 10 pc. b. farther than 10 pc. c. No way to tell.
At what phase are the tides least noticeable?
A) New Moon B) Full Moon C) Third quarter D) Waxing crescent E) Waning gibbous
You and a classmate are discussing how much work one must do to lift a box of mass m a vertical distance h. Your classmate argues, “You have to exert an upward force on the box at least equal in magnitude to the box’s weight 
, and you lift the box upward a distance h, so you must do work equal to 
. But in addition,” your classmate continues, “ you must increase the box’s gravitational potential energy by 
to lift the box.” What amount of work do you think you need to do on the box to lift it a height h? Be prepared to defend your response. (Hint: What is the system here?)
A. Zero work
B. About 
(if you move the box slowly)
C. Significantly greater than 
but less than 
D. About 
(if you move the box slowly)
E. Significantly greater than 
He discovered what we now call Newton's first law of motion
A) Copernicus B) Galileo C) Ptolemy D) Tycho Brahe E) Kepler