Observing star clusters will give astronomers needed data for stellar evolution because all the stars in the cluster have the same ____
a. masses
b. temperatures
c. ages
d. luminosities
e. apparent magnitudes
c
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In contrasting the distribution of the X-ray and gamma-ray bursts, we find:
A) gamma ray bursts are far closer to us, so they appear more luminous. B) gamma ray bursts are far beyond our Galaxy, at cosmological distances, and spread all over the sky, not in the plane of our Galaxy. C) gamma ray bursts are more closely associated with open than globular clusters. D) gamma ray bursts can repeat, while the X-ray bursts do not. E) gamma ray bursts can be observed from the ground, but X-rays are blocked by the ionosphere for ground based observers.
Which of the following is the most basic definition of a greenhouse gas?
A) a gas that reflects a lot of sunlight B) a gas that keeps warms air from rising, and therefore warms the surface C) a gas that absorbs infrared light D) a gas that makes a planet much hotter than it would be otherwise, even in small amounts
A student releases a ball from rest on an inclined plane and measures that it travels a distance of 0.5 m in a time of 2.0 s. The acceleration of the ball is
A. 0.25 m/s2. B. 0.125 m/s2. C. 0.5 m/s2. D. 1.0 m/s2.
You experience night-time when
A) the Moon blocks the Sun's light. B) Earth is on the opposite side of the celestial sphere from the Sun. C) you are located on the side of the Earth that faces away from the Sun. D) you are located on the side of the Earth that faces toward stars.