Three identical blocks of masses m = 2 kg are drawn by a force 10.2 N on a frictionless surface. What is the tension (in newton) in the string between the blocks B and C?

Given, m1=m2=m3=2 kg,F=10.2 NThe FBD of given system is as shown belowFor body A, F - T1 = ma         ......(i)For body B,  T1 - T = ma         ......(ii)For body C,  T = ma         ......(iii)Adding Eqs. (i), (ii) and (iii), we getF=3ma⇒a=10.23×2=1.7 ms-2Alternately Acceleration can be found as net acceleration of a system, i.e.a= Total net force  Total mass =10.2(2+2+2)=10.26=1.7 ms-2So, net tension in string between the blocks B and C isT = m × a = 2 × 1.7 = 3.4 N