Two solid rubber balls $A$ and $B$ having masses $200$ and $400\, gm$ respectively are moving in opposite directions with velocity of $A$ equal to $0.3 \,m/s$. After collision the two balls come to rest, then the velocity of $B$ is .............. $\mathrm{m} / \mathrm{s} $
Two solid rubber balls $A$ and $B$ having masses $200$ and $400\, gm$ respectively are moving in opposite directions with velocity of $A$ equal to $0.3 \,m/s$. After collision the two balls come to rest, then the velocity of $B$ is .............. $\mathrm{m} / \mathrm{s} $
$0.15$
$1.5 $
$-0.15$
None of the above
Two solid rubber balls $A$ and $B$ having masses $200$ and $400\, gm$ respectively are moving in opposite directions with velocity of $A$ equal to $0.3 \,m/s$. After collision the two balls come to rest, then the velocity of $B$ is .............. $\mathrm{m} / \mathrm{s} $
Initial linear momentum of system = ${m_A}{\vec v_A} + {m_B}{\vec v_B}$
$= 0.2 × 0.3 + 0.4 × v_B$
Finally both balls come to rest
final linear momentum $= 0$
By the law of conservation of linear momenum
$0.2 × 0.3 + 0.4 × v_B = 0$
${v_B} = - \frac{{0.2 \times 0.3}}{{0.4}} = - 0.15\;m/s$
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