dark matter may explain
a. unexpected orbital velocities of stars in galaxies
b. the source of energy that fuels stars
c. the expansion of the universe
d. the origin of life
e. what came before the big bang

and dont you dare say e.

You have been called to testify as an expert witness in a trial involving a head-on collision. car a weighs 1515 lb and was traveling eastward. car b weighs 1125 lb and was traveling westward at 44.0 mph. the cars locked bumpers and slid eastward with their wheels locked for 22.5 ft before stopping. you have measured the coefficient of kinetic friction between the tires and the pavement to be 0.750 . how fast (in miles per hour) was car a traveling just before the collision? (this problem uses english units because they would be used in a u. s. legal proceeding.)

At what time will the interfering waves have an amplitudeof zero?

The built in flash in a compact camera is usally capable of giving correct exsposure for distance up to how many meters?