• # question_answer Two blocks of mass ${{M}_{1}}=20\,kg$ and ${{\operatorname{M}}_{2}}=12\operatorname{K}\operatorname{g},$ are connected by a metal rod of mass 8 kg. The system is pulled vertically up applying a force of 480 N as shown. The tension at mid-point of the rod is:                         [JEE ONLINE 22-04-2013] A)             $144$ N B) $96$ N C)             $240$ N D) $192$ N

 [d] Acceleration produced in upward direction $\text{a =}\frac{\text{F}}{{{\text{M}}_{\text{1}}}\text{+}{{\text{M}}_{\text{2}}}\text{+ Mass of metal rod}}$ $=\frac{480}{20+12+8}=12m{{s}^{-2}}$ Tension at the mid-point $\text{T =}\left( {{\text{M}}_{\text{2}}}\text{+}\frac{\text{Mass of rod}}{\text{2}} \right)\text{a}$ $=(12+4)\times 12=192N$ [d] When the body has maximum speed then