More questions in the image.

true or false: the arrows on a motion map should point in the direction of motion.
true
false

1) in a motion map the arrows point in which direction the object is moving, but if there are other arrows in the map (like forces and such) those may point in other direction, so if only movement (velocity) arrows are depicted, this is true.

2) True, as "longer" is the arrow, bigger is the magnitude represented (again, arrows may depict other things than velocity)

3) If only velocity arrows are depicted, this is true, because the velocity is zero, then there is no arrow of velocity.

If other arrows are depicted, like acceleration or force, those may be in there in regards that the object is not moving.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s