Stars are mostly made of
A) hydrogen and helium
B) pure hydrogen
C) carbon, hydrogen, oxygen and nitrogen
D) an equal mixture of all elements
A
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Moment of Inertia: A majorette fastens two batons together at their centers to form an X shape. Each baton consists of an extremely light 1.2-m bar with small 0.25-kg balls at each end. What is the moment of inertia of this baton about an axis through the center of the X?
Fill in the blank(s) with the appropriate word(s).
The strength of a rope depends on its
A) thickness. B) length. C) both of these
A mass of 1.0 kg is pushed against a spring with a spring constant of 25 N/m. As a result, the spring is compressed by 20 cm. The mass is then released
(a) What is the amount of potential energy acquired by the spring when it is compressed? (b) What is the kinetic energy of the mass after the mass is released and it is no longer in contact with the spring?
A third quarter moon is visible
a. near the eastern horizon just before sunrise. b. near the eastern horizon just after sunset. c. in the southern sky at sunrise. d. in the southern sky at sunset. e. from sunset until sunrise.