Astronomers generally can measure a star's mass if only it is a member of a binary star system. What characteristics of the stars must we know to measure the masses of the stars in a binary system?
A) their spectral types and their distance from Earth
B) their absolute magnitudes and their luminosities
C) their orbital period and average orbital distance
D) their luminosities and distance from Earth
C) their orbital period and average orbital distance
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Which of the following metals should not be in electrical contact with a critical structure made of low carbon steel that is used in a sea water environment?
(a) Cadmium (b) 2024 aluminum (c) Copper (d) Magnesium
A charge of 2.00 ?C flows onto the plates of a capacitor when it is connected to a 12.0-V potential source. What is the minimum amount of work that must be done in charging this capacitor?
A) 6.00 µJ B) 24.0 µJ C) 12.0 µJ D) 144 µJ E) 576 µJ
When a vertically falling firecracker bursts, the vector sum of momentum fragments
A) in the horizontal direction cancels to zero. B) in the vertical direction equals the momentum of the firecracker before bursting. C) both of these D) neither of these
A uniform linear charge of 2.0 nC/m is distributed along the x axis from x = 0 to x = 3 m. Which of the following integrals is correct for the x component of the electric field at y = 2 m on the y axis?
A.
B.
C.
D.
E.