Dear student
On square forces are equal in magnitude.
Hence
Resultant = AB +2 BC + 2CD + DA (in vectors)
Let AB = p vector
Hence
BC = p vector
Now
CD = -p vector
Da = -p vector
Hence
Resultant = p + 2p -2p -p
= 0
Hence resultant will be 0 (zero)
Regards
Arun (askIITians forum expert)