Question

Three equal weighs of mass 2kg each are hanging by a string passing over a fixed pulley. The tension in the string (in N) connecting B and C is:

• A. 4 g/3
• B. g/3
• C. 2g/3
• D. g/2

Answer 1

Answer: (A)

4 g/3

The tension in the string connecting block A and B will be same as there is no friction in Pulley . Also the magnitude of acceleration of A ,B and C will be same .

So for A , $T-mg=ma$

$T-2g=2a$ ...(1)

for block B

Let the tension in string connecting BC be $T_{BC}$

$T_{BC}+mg-T=ma$

$T_{BC}+2g-T=2a$ ...(2)

For block C

$mg-T_{BC}=ma$

$2g-T_{BC}=2a$ ..(3)

on solving all three above equation

$T_{BC}=\frac{4g}{3}$