Scientists suspect that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth?
A) Mars's interior has cooled so much that its molten core layer no longer undergoes convection.
B) Mars rotates much slower than the Earth.
C) The Martian core is made of rock, while Earth's core is made of metal.
D) Mars is too far from the Sun to have a global magnetic field.
A) Mars's interior has cooled so much that its molten core layer no longer undergoes convection.
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Graphical Addition: If 
+ 
= 
and their magnitudes are given by A + B = C, then the vectors 
and 
are oriented
A. perpendicular relative to one other. B. parallel to each other (in the same direction). C. antiparallel to each other (in opposite directions). D. It is impossible to know from the given information.
While spinning down from 500 rpm to rest, a flywheel does of work. This flywheel is in the shape of a solid uniform disk of radius 1.2 m. What is the mass of this flywheel?
A) 4.0 kg B) 3.4 kg C) 4.6 kg D) 5.2 kg
A block of metal weighs 40 N in air and 30 N in water. What is the buoyant force that the water exerts on the block? The density of water is 1000 kg/m3
A) 10 N B) 30 N C) 40 N D) 70 N
The resultant force vector R (in newtons) is:
Bracket ADO is acted on by forces F and T and couple M (see figure). Assume that F 5 8 N, T 5 9 N and
M 5 12 N?m. Joint coordinates are in meters.
(A) -5i + 7j + 1k
(B) -3i + 4j - 3k
(C) -6i + 5j + 4k
(D) -3i + 6j + 2k
