F = Bib
So, a = Bib/m
So, it will undergo uniform acceleration till the wire reaches the end of the strips, after that it will undergo uniform decelration due to friction.
uniform acceleration till t=√2ml/iBb
speed of the wire till it reaches the end of the strips
v2 = 2(Bib/m)l
=> v = √2iBbl/m
Now, conserving energy,
mv2/2 = μmgx ... where x is the distance traveled by wire till it stops
=> iBbl = μmgx
=> x = iBblμmg