Three equal weight `A,B` and `C` of mass `2kg` each are hanging on a string passing over a fixed frictionless pulley as shown in the figure. The tension in the string connecting weights `B` and `C` is approximately

Options

A. zero
B. 13N
C. `3.3N`
D. `19.6N`

Answer

B

Explanation

For A: `T-2g=2a` (i)
For B: `T_(1)+2g-T=-2a` (ii)
For C: `2g-T_(1)=2a` (iii)
Adding equation (i) and (ii),
we get `T_(1)=4a` (iv)
From equation (iii) and (iv) `2g-4a=2a` or `a=g//3` (v)
From equation (iv) and (v), `T_(1)=4xx(g)/(3)=13N`