Which statement is the best description of the Milky Way galaxy? A. a group of planets revolving around a single star.
B. a collection of stars and gases with the sun as its center.
C. a collection of gases held together by inertia.
D. a group of stars, dust, and planets held together by gravity.

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) determine the magnitude and direction of projectile velocity at t= 1.3s b) determine the magnitude and direction of projectile acceleration at t=1.3s

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

How many atoms of nitrogen are in the chemical formula ni(w on