Two moving billiard balls, each with a mass of M, undergo an elastic collision. Immediately before the collision, ball A is moving east at 2 m/s and ball B is moving east at 4 m/s. a. In terms of M, what is the total momentum (magnitude and direction) immediately before the collision?

b. The final momentum, M(vA, f + vB, f), must equal the initial momentum. If the final velocity of ball A increases to 4 m/s east because of the collision, what is the final momentum of ball B?

c. For each ball, compare the final momentum of the ball to the initial momentum of the other ball. These results are typical of head-on elastic collisions. What generalization about head-on elastic collisions can you make?

You need to be more specific.  i really don't know what a "motion map" is.you can draw a graph of an object's position, distance, displacement, speed,velocity, or acceleration versus time, or you can draw a graph of the object's x-position versus its y-position and not give any information about time at all.if the graph presents position or displacement against time,  then constant velocity is a straight line . . i.e. a line that has  constant slope.if the graph shows speed against time, then constant velocityis a horizontal piece of line.if the graph shows acceleration against time, then constant  velocity is a piece of line that lies on the x-axis . . it's value is zero. 

Stars are born within the clouds of dust and scattered throughout most galaxies. a familiar example of such as a dust cloud is the orion nebula. turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. as the cloud collapses, the material at the center begins to heat up. known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star. three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs; this would explain why the majority the stars in the milky way are paired or in groups of multiple stars.therefor, i would say the answer is: dust and gases contract.i hope this ! < 3

What happens is they connect and there

The best answer would be the first option a).