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
A body is moving with a velocity v, breaks up into two equal parts. One of the part retraces back with velocity v. Then the velocity of the other part is [DCE 2004]
A) v in forward direction
B) 3v in forward direction
C) v in backward direction
D) 3v in backward direction
Correct Answer:
B
Solution :
Let the initial mass of body = m Initial linear momentum = \[mv\] ?(i) When it breaks into equal masses then one of the fragment retrace back with same velocity \ Final linear momentum = \[\frac{m}{2}(-v)+\frac{m}{2}({{v}_{2}})\] ?(ii) By the conservation of linear momentum Þ \[mv=\frac{-mv}{2}+\frac{m{{v}_{2}}}{2}\]Þ \[{{v}_{2}}=3v\] i.e. other fragment moves with velocity 3v in forward direction