question_answer

Consider the arrangement shown in figure where two blocks are connected by a uniform rope of mass 4 kg. The arrangement is lifted up vertically by a constant vertical force of magnitude 150 N. The ratio of tension in the rope at A to that at B would be

A)  2                                

B)  4                    

C)       \[\frac{3}{4}\]                                   

D)  \[\frac{5}{4}\]

Correct Answer: A

Solution :

F. B. D of rope +4 kg block: \[{{T}_{A}}-8g=8a\] \[\Rightarrow \]\[{{T}_{A}}=8(a+g)\]                                          (1) F. B. D of 4g. block: \[{{T}_{B}}-4g=4a\] \[\Rightarrow \]\[{{T}_{B}}=4(a+g)\]                                          (2) Dividing equation (1) by (2), we get \[\frac{{{T}_{A}}}{{{T}_{B}}}=2\] Hence, the correction option is [a].