Define like and unlike forces

Like forces are the forces that are parallel to each other and have the same direction. Unlike forces are the forces that parallel yet have directions inverse to each other.

hope this helps :)

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

c. magnitude and direction