How do we know that quasars are very distant objects?
A) from their high luminosities
B) from the fact that they can vary in luminosity in short time periods
C) by observing Cepheid variables within them
D) from their large redshifts
E) by measuring their parallax angles
D) from their large redshifts
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Two identical balls are thrown from the top of a building with the same speed. Ball 1 is thrown horizontally, while ball 2 is thrown at an angle ? above the horizontal
Neglecting air resistance, which ball will have the greatest speed when hitting the ground below? A) Ball 1 B) Ball 2 C) Both balls reach the ground with the same speed. D) Cannot be determined without knowing the height of the building. E) Cannot be determined without knowing the time each ball is in the air.
A nonuniform linear charge distribution given by l(x) = bx, where b is a constant, is distributed along the x axis from x = 0 to x = +L. If b = 40 nC/m2 and L = 0.20 m, what is the electric potential (relative to a potential of zero at infinity) at the point y = 2L on the y axis?
a. 19 V b. 17 V c. 21 V d. 23 V e. 14 V
A blob of clay, mass M, is propelled upward from a spring that is initially compressed by an amount d. If, upon its release, the clay reaches an ultimate height of h above the unstretched spring’s end, what is the spring constant k?
a. 
b. 
c. 
d. 
What stage of star formation is the zero-age main sequence?
What will be an ideal response?