Question

Two blocks of mass $M_1=20kg$ and $M_2=12kg$ are connected by a metal rod of mass $8kg$. the system is pulled vertically up by applying a force of $480N$ as shown. The tension at the mid-point of the rod is

• A. $114N$
• B. $96N$
• C. $240N$
• D. $192N$

Answer 1

The correct option is D $192N$

The total mass of the system $=20+12+8=40kg.$

The gravitational force ${}^{\prime }{g}^{\prime }=10$

$ma=F-mg$

$40a=480-40\times 10$

$a=2m/s^2$

At the midpoint of the rod$,$ half of the rod and $M_2$ are below, having total mass of $4+12=16kg.$

Therefore Tension$,T=m(g+a)=16(10+2)=192N$

Hence,

option $\left(D\right)$ is correct answer.