Question

Two blocks $A$ and $B$ are connected by a massless string ( shown in figure) . $A$ force of $30N$ is applied on block $B$ . The distance travelled by centre of mass in $25$ starting from rest is

• A. $1m$
• B. $2m$
• C. $3m$
• D. None of these

Answer 1

Answer: (B)

$2m$

The acceleration of centre of mass is
$a_{C}M=\frac{F}{m_A+m_B}$
$\frac{30}{10+20}=1m/s$
$\therefore Distances=\frac{1}{2}{a}_{C}M{t}^2$
$\frac{1}{2}\times 1\times 2^2=2m$