Light waves, Ocean waves and Microwaves are examples of

Electromagnetic Waves

Explanation:

Light waves are just one type of electromagnetic wave. Other electromagnetic waves include the microwaves in your oven, radio waves, and X-rays. Light waves are regarded as a varying electric field (E) coupled with a varying magnetic field (B), at right angles to each other and to the direction of travel.

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