Question

PLS. EXPLAIN ME THE NEWTON'S THIRD LAW OF MOTION & CONSERVATION OF MOMENTUM???????? REQUEST U 2 REPLY FAST............

Answer 1

for every action there is equal and opposite reaction 

When you try to try to push the wall it applies equal and opposite force such that net force is zero

conservation of momentum:

M1u1+M2u2= M1v1+M2v2
initial momentum is equal to final momentum

such that net momentum of the system is conserved