A body of mass $50\, kg$ is projected vertically upwards with velocity of $100 \,m/sec$. $5 \,seconds$ after this body breaks into $20\, kg$ and $30 \,kg$. If $20\, kg $ piece travels upwards with $150 \,m/sec$, then the velocity of other block will be
A body of mass $50\, kg$ is projected vertically upwards with velocity of $100 \,m/sec$. $5 \,seconds$ after this body breaks into $20\, kg$ and $30 \,kg$. If $20\, kg $ piece travels upwards with $150 \,m/sec$, then the velocity of other block will be
$15 \,m/sec$ downwards
$15\, m/sec$ upwards
$51\, m/sec$ downwards
$51\, m/sec$ upwards
A body of mass $50\, kg$ is projected vertically upwards with velocity of $100 \,m/sec$. $5 \,seconds$ after this body breaks into $20\, kg$ and $30 \,kg$. If $20\, kg $ piece travels upwards with $150 \,m/sec$, then the velocity of other block will be
Velocity of $50 \,kg$. mass after $5 \,sec $ of projection $v = u - gt$$ = 100 - 9.8 \times 5 = 51\;m/s$
At this instant momentum of body is in upward direction
${P_{{\rm{initial}}}} = 50 \times 51 = 2550\;kg - m/s$
After breaking $20\, kg$ piece travels upwards with $150 \,m/s$ let the speed of $30 \,kg$ mass is $V$
${P_{{\rm{final}}}} = 20 \times 150 + 30 \times V$
By the law of conservation of momentum
${P_{{\rm{initial }}}} = {P_{{\rm{final}}}}$
==> $2500 = 20 \times 150 + 30 \times V \Rightarrow V = - 15\;m/s$
i.e. it moves in downward direction.
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