Mars' magnetic field is so weak because
A) it spins much slower than Earth does.
B) it core may no longer be molten.
C) its core contains less iron than our own.
D) Both B and C are probable.
E) All of the above are correct.
D
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An object of mass m moving with a certain speed has a kinetic energy of 0.0124 J. The object collides with a horizontal spring and compresses it by 0.800 m before it is brought to rest. What is the spring constant of this spring?
A) 0.315 N/m B) 0.150 N/m C) 0.194 N/m D) 0.0235 N/m E) 0.0388 N/m
One of the primary justifications given, in the textbook's opening section, for this course is
A) so that you can learn useful skills such as the ability to repair things around the house. B) to transmit our cultural heritage to your generation and to future generations. C) because more broadly educated people get better-paying jobs upon graduation. D) the evolutionary trend over billions of years has been toward increased awareness. E) people with a broad education are happier.
A cable is 100 m long, has a cross-sectional area of 1.0 mm2, and is made of a material having a Young's modulus of 1.0 × 1011 N/m2. If a 1000-N force is applied to stretch the cable, how far does it stretch?
A) 0.0010 m B) 0.010 m C) 0.10 m D) 1.0 m E) 10 m
A magician can make a candle look as if it is burning under water by focusing light from a candle flame burning in air directly on top of an underwater candle. To do this you want to use a (Hint: eliminate those that cannot work.)
a. concave mirror farther than one focal length from the burning candle. b. a convex mirror farther than one focal length from the burning candle. c. a biconcave lens farther than one focal length from the burning candle. d. a concave mirror closer than one focal length to the burning candle. e. a convex lens closer than one focal length to the burning candle.