Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति
JEE Main & Advanced
Physics
Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति
Question Bank
Elastic and Inelastic Collision
question_answer
A body of mass 5 kg explodes at rest into three fragments with masses in the ratio 1 : 1 : 3. The fragments with equal masses fly in mutually perpendicular directions with speeds of 21 m/s. The velocity of the heaviest fragment will be [CBSE PMT 1991]
A) 11.5 m/s
B) 14.0 m/s
C) 7.0 m/s
D) 9.89 m/s
Correct Answer:
D
Solution :
\[{{P}_{x}}=m\times {{v}_{x}}=1\times 21=21\ kg\ m/s\] \[{{P}_{y}}=m\times {{v}_{y}}=1\times 21=21\ kg\ m/s\] \ Resultant =\[\sqrt{P_{x}^{2}+P_{y}^{2}}=21\sqrt{2}\]kg m/s The momentum of heavier fragment should be numerically equal to resultant of \[{{\vec{P}}_{x}}\] and \[{{\vec{P}}_{y}}\]. \[3\times v=\sqrt{P_{x}^{2}+P_{y}^{2}}=21\sqrt{2}\]\ \[v=7\sqrt{2}\] = 9.89 m/s