Answer:using Newton third law
Let initial velocity of block be u1=3m/s
Mass of moving block m1 =1kg
Final velocity of block =V
Mass of stationary block m2= 4kg
Since they stick together, their final velocity will be the same.
m1u1 + m2u2=(m1+m2)v
(1*3)+(0*4)=(1+4)v
3=5v
Divide both sides by 5
V=0.6
Final velocity is 0.6m/s
Step-by-step explanation: