What important change in the Sun over the past four billion years is thought to be very important to understanding the climates of Venus, Earth, and Mars?
A) a gradual weakening of the solar wind with time
B) a gradual dimming with time
C) a gradual brightening with time
D) a gradual reduction in the amount of ultraviolet and X-ray radiation coming from the Sun
C
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Mass on a Spring: A 51.8-kg bungee jumper jumps off a bridge and undergoes simple harmonic motion. If the period of oscillation is 11.2 s, what is the spring constant (force constant) of the bungee cord?
A. 16.3 N/m B. 19.6 N/m C. 26.1 N/m
White-dwarf supernovae are good standard candles for distance measurements for all the following reasons except which?
A) All white-dwarf supernovae involve the explosion of stars of nearly the same mass. B) White-dwarf supernovae are so bright that they can be detected even in very distant galaxies. C) White-dwarf supernovae are common enough that we detect several every year. D) White-dwarf supernovae occur only among young and extremely bright stars. E) All white-dwarf supernovae have similar light curves, which makes them easy to distinguish from massive-star supernovae.
Contrast S and P waves in terms of speed and transmission through the interior
What will be an ideal response?
A 2.0-kg object moving 3.0 m/s strikes a 1.0-kg object initially at rest. Immediately after the collision, the 2.0-kg object has a velocity of 1.5 m/s directed 30° from its initial direction of motion. What is the x component of the velocity of the 1.0-kg object just after the collision?
a. 3.7 m/s b. 3.4 m/s c. 1.5 m/s d. 2.4 m/s e. 4.1 m/s