Energy that flows from somthing with a higher temperature to something with a lower temperature is

Heat Transfer

Explanation:

This is called heat transfer. Heat transfer is the process in which energy flows from a matter that is higher in heat to a matter that is cooler, until the two matters reach the same temperature.

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

do you have a formula possibly