Two masses m_1 and m_2 (m_1 gt; m_2) ar

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Two masses $m_1$ and $m_2$ ($m_1$ > $m_2$) are connected by massless flexible and inextensible string passed over massless and frictionless pulley. The acceleration of center of mass is

A

${\left( {\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}} \right)^2}g$

B

$\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}g$

C

$\frac{{{m_1} + {m_2}}}{{{m_1} - {m_2}}}g$

D

Zero

Two masses $m_1$ and $m_2$ ($m_1$ > $m_2$) are connected by massless flexible and inextensible string passed over massless and frictionless pulley. The acceleration of center of mass is

Acceleration of each mass $ = a = \left( {\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}} \right)\;g$

Now acceleration of centre of mass of the system

${A_{cm}} = \frac{{{m_1}\overrightarrow {{a_1}} + {m_1}\overrightarrow {{a_2}} }}{{{m_1} + {m_2}}}$

As both masses move with same acceleration but in opposite direction so

$\overrightarrow {{a_1}} = - \overrightarrow {{a_2}} $ = a (let)

$\therefore \;\;{A_{cm}} = \frac{{{m_1}a - {m_2}a}}{{{m_1} + {m_2}}}$

$ = \left( {\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}} \right) \times \left( {\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}} \right) \times g$

$ = {\left( {\frac{{{m_1} - {m_2}}}{{{m_1} + {m_2}}}} \right)^2} \times g$