The semi major axis of an ellipse is
a. the ratio of the longest diameter of the ellipse to that of the shortest diameter of the ellipse.
b. half the length of the shortest diameter of the ellipse.
c. half the length of the longest diameter of the ellipse.
d. the distance between the two foci of the ellipse.
e. the ratio of the distance between the two foci to the length of half the longest diameter of the ellipse.
Question 2The free-fall contraction of a molecular cloud
a. can be initiated by shock waves from supernovae.
b. can be initiated by nearby spectral type G stars.
c. can be initiated by the rotation of the cloud.
d. causes the cloud to become transparent to ultraviolet radiation.
e. causes the particles in the cloud to decrease the speed with which they move.
Question 3The geometry of an ellipse is described by two numbers: the ____ which is half the longest diameter of the ellipse and the ____ which tells us the shape of the ellipse.
a. radius, eccentricity
b. radius, deferent
c. semi major axis, deferent
d. semi major axis, epicycle
e. semi major axis, eccentricity
Question 4What causes the outward gas pressure that balances the inward pull of gravity in a main sequence star?
a. The rapid outward flow of gas.
b. The rapid inward flow of the gas.
c. The high temperature of the gas.
d. The high density of the gas.
e. c and d
Question 5____ occur when the moon is first or third quarter.
a. Neap tides
b. Spring tides
c. Total solar eclipses
d. Annular eclipses
e. A coppery red moon will
Question 6The carbon-nitrogen-oxygen cycle
a. operates at a slightly lower temperature than the proton-proton chain.
b. is most efficient in star less massive than the sun.
c. occurs when carbon and oxygen combine to form nitrogen, which produces energy.
d. produces the energy responsible for bipolar flows.
e. combines four hydrogen nuclei to form one helium nucleus, which produces energy.
Quick Reply
