Three blocks connected together by strings are pulled along a horizontal surface by applying a force F. If F=36N , What is the tension $T_2$?

 

Suppose the system slides with acceleration ‘a’.
 $m_1=1kg,m_2=8kg,m_3=27kg$
 $F-T_2=m_{3}a,T_2-T_1=m_{2}a,T_1=m_{1}a$
Solving the above equations, we get
 $a=\frac{F}{m_1+m_2+m_3}=\frac{36}{1+8+27}=\frac{36}{36}=1m{s}^{-2}$
From the above equation,  $T_2=F-m_{3}a$
 $T_2=36-27\times 1=9N$