What are the two possible explanations for not seeing something glowing brightly along every line-of-sight?
I) The universe is infinite in size and infinitely old, but dust absorbs starlight from far away stars.
II) The universe has a finite number of stars.
III) The universe is changing in some way as to prevent us from seeing an infinite number of stars.
A) I and III B) II and III C) I and II
B
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The fresh newly created surfaces of icy satellites of Jovian planets
a. appear dark in color with few impact craters. b. appear dark in color with many impact craters. c. appear very bright because fresh ice is very reflective. d. generally show long bright grooves and a modest number of impact craters. e. generally have small volcanoes that are active.
An object that weighs 2.450 N is attached to an ideal massless spring and undergoes simple harmonic oscillations with a period of 0.640 s. What is the spring constant of the spring?
A) 2.45 N/m B) 12.1 N/m C) 24.1 N/m D) 0.102 N/m E) 0.610 N/m
In beta minus decay, the number of protons in the nucleus is
A) decreased by 1. B) decreased by 2. C) increased by 1. D) increased by 2. E) remains unchanged.
You ride in an automobile traveling at 100 km/h. It comes to a stop over 0.5 seconds. You can be sure that
a. the car's engine has stopped. b. a velocity acts. c. friction between the tires and the road stopped it. d. the car had a nonzero acceleration during that time. e. none of the other answers is correct.