At time A, is the expansion of the universe accelerating, coasting, or decelerating?
What will be an ideal response?
Accelerating
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Which scientists played a major role in overturning the ancient idea of an Earth-centered universe, and about when?
A) Copernicus, Kepler, and Galileo; about 400 years ago B) Aristotle and Copernicus; about 400 years ago C) Newton and Einstein; about 100 years ago D) Huygens and Newton; about 300 years ago E) Aristotle and Plato; about 2,000 years ago
One philosophical difference between Newtonian and modern physics is that, unlike modern physics, Newtonian physics
A) assumes that the universe is made of separate and independently existing parts. B) makes predictions that contain an essential element of uncertainty. C) is based on abstract concepts and is thus difficult or impossible to picture. D) emphasizes the interaction between the observer and the thing observed. E) has no way of dealing with energy and other abstract concepts.
A 1.86-kg block is held in place against the spring by a 81-N horizontal external force (see the figure). The external force is removed, and the block is projected with a velocity v1 = 1.2 m/s upon separation from the spring
The block descends a ramp and has a velocity at the bottom. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction over this section is 0.28. The velocity of the block is v3 = 1.4 m/s at C. The block moves on to D, where it stops. The height h of the ramp is closest to A) 11 B) 7.3 C) 15 D) 17 E) 18
Why do astronomers narrow their search to the "habitable zone" of other star systems?
a. the most likely place to support planets with thick atmospheres b. the least likely place to have zero ultraviolet radiation c. the most likely place with liquid water, and extraterrestrial life d. the most likely place to have oxygen in the atmosphere e. the least likely place to have wide temperature ranges on the surfaces of planets