Question

Same spring is attached with $2kg$, $3kg$ and $1kg$ blocks in three different cases as shown in figure. If $x_1,x_2$ and $x_3$ be the extensions in the spring in these cases then (Assume all the blocks to move with uniform acceleration)

• A. $x_1=0,x_3>x_2$
• B. $x_2>x_1>x_3$
• C. $x_3>x_1>x_2$
• D. $x_1>x_2>x_3$

Answer 1

Answer: (B)

If $m_1$ and $m_2$ are masses of blocks then tension $T$ in the string as well as spring are

$T=\frac{2m_1{m}_2}{m_1+m_2}g$

$T_1=2g$,

$T_2=2.4g$

and $T_3=1.33g$

$\therefore T_2>T_1>T_3$

or $x_2>x_1>x_3$

$t=\frac{v_0}{g}=\frac{(10/3)}{10}$

$=\frac{1}{3}sec$