Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति
JEE Main & Advanced
Physics
Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति
Question Bank
Conservation of Energy and Momentum
question_answer
An object of mass 3m splits into three equal fragments. Two fragments have velocities \[v\hat{j}\] and \[v\hat{i}\]. The velocity of the third fragment is [UPSEAT 2004]
A) \[v(\hat{j}-\hat{i})\]
B) \[v(\hat{i}-\hat{j})\]
C) \[-v(\hat{i}+\hat{j})\]
D) \[\frac{v(\hat{i}+\hat{j})}{\sqrt{2}}\]
Correct Answer:
C
Solution :
Initial momentum of 3m mass = 0 ?(i) Due to explosion this mass splits into three fragments of equal masses. Final momentum of system = \[m\vec{V}+mv\hat{i}+mv\hat{j}\] ?(ii) By the law of conservation of linear momentum \[m\vec{V}+mv\hat{i}+mv\hat{j}=0\]Þ \[\vec{V}=-v(\hat{i}+\hat{j})\]