You lift a 10. lb physics book up in the air a distance of 1 ft, at a constant velocity of 0.5 ft/s. The work done by gravity is
A) +5 ft?lb.
B) -10 ft?lb.
C) -5 ft?lb.
D) zero.
E) +10 ft?lb.
B
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Project a cannonball from atop Newton's hypothetical mountain at 8 km/s and it orbits Earth. Project it at 9 km/s and the shape of the orbit is
A) a somewhat larger circle. B) a wide parabola. C) an ellipse.
If the enter full moon passes through the earths umbra, we will see
a)partial solar eclipse b)penumbral lunar eclipse c) total lunar eclipse d) annular eclipse
Consider two diffraction gratings; one has 4000 lines per cm and the other one has 6000 lines per cm
A) The 4000-line grating produces the greater dispersion. B) Both gratings produce the same dispersion, but the orders are sharper for the 4000-line grating. C) Both gratings produce the same dispersion, but the orders are sharper for the 6000-line grating. D) The 6000-line grating produces the greater dispersion.
How is RNA different from DNA?
A) its monomers do not contain nucleotide bases B) it is single stranded rather than consisting of a double helix C) it consists of a triple helix rather than a double helix D) its strands are much longer than DNA