What do slinky waves and seismic waves have in common?

Slinky waves refer to the waves represented by a spring/ slinky. It can be used to represent both longitudinal and transverse. Refer attached images below.  Similarly, the seismic waves are of two types - longitudinal waves (P-type) and transverse waves (S-type). During an earthquake, the rupturing process causes the seismic waves to transfer energy without moving any material from one place to another. the P-type waves are faster than the S-types waves.  

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