What does the luminosity of a main-sequence star tell us?
A) the star's distance from us
B) the rate at which it converts hydrogen to helium
C) the star's radius
D) the star's surface temperature
B) the rate at which it converts hydrogen to helium
You might also like to view...
The formation of the supercontinent of Pangaea caused
A) a worldwide rise in sea level. B) a worldwide drop in sea level. C) no change in sea level. D) none of these
As measured from the Earth, a spacecraft is moving at speed 0.80c toward another spacecraft moving at speed 0.60c in the same direction, i.e., the first spacecraft is catching up with the second spacecraft. What is the speed of the first spacecraft as viewed from the second spacecraft?
a. 0.38c b. –0.20c c. –0.38c d. not given
What is the resistance of 1.0 m of a solid cylindrical metal cable having a diameter of 0.40 inches and a resistivity of 1.68 × 10-8 ? ? m?
A) 0.00012 ? B) 0.00021 ? C) 0.0012 ? D) 0.0021 ?
Consider a situation where you exert a force F on a crate of mass m, moving it at a speed v a distance d across a floor in a time interval t. The potential energy of the crate is __________
Fill in the blank(s) with correct word