Three blocks of masses ` m _ 1 , m _ 2 and m_ 3 ` are connected by mass less string as shown kept on a frictionless table.

They are pulled with a force ` T _ 3 = 40 N. ` If ` m _ 1 = 10 kg, m _ 2 = 6 kg and m _ 3 = 4kg`, the tension ` T _ 2 ` will be

Options

A. 10 N
B. 20 N
C. 32 N
D. 40 N

Answer

B

Explanation

The common acceleration of the blocks is
` a= ( 40)/( 10+6+4 ) = ( 40)/(20 ) = 2m//s^2`
` therefore ` tension ,`T_2 = (m_2 + m_3 ) a = ( 6+4 )2 = 10 xx 2 = 20 N`