How do astronomers measure the mass of a supermassive blackhole?
a) by comparing its apparent magnitude to its absolute brightness
b) by comparing its X-ray luminosity to its radio luminosity
c) using the formula E = mc2
d) by measuring the speed at which stars move in its vicinity
e) by measuring its parallax
Ans: d) by measuring the speed at which stars move in its vicinity
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If light from a distant star passes close to a massive body, the light beam will:
A) bend towards the star due to gravity. B) continue moving in a straight line. C) change color to a shorter wavelength. D) slow down. E) accelerate due to gravity.
Which of the following lists the stages of life for a low-mass star in the correct order?
A) protostar, main-sequence star, red giant, planetary nebula, white dwarf B) protostar, main-sequence star, red giant, supernova, neutron star C) protostar, main-sequence star, planetary nebula, red giant D) main-sequence star, white dwarf, red giant, planetary nebula, protostar
The bottom of a flat-bottomed aluminum boat has area = 4.10 m2 and mass = 65.0 kg. If two fishermen and their fishing gear with total mass of 305 kg are placed in the boat, how much lower will the boat ride in the water? (H2O density = 1.0 × 10^3 kg/m3)
a. 0.0159 m b. 0.0585 m c. 0.0744 m d. 0.0902 m e. 1.25 m
The type of rock most susceptible to chemical weathering is
a. sandstone. b. basalt. c. shale. d. limestone.