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 bomb of mass \[30kg\]at rest explodes into two pieces of masses \[18\,kg\] and \[12\,kg\]. The velocity of \[18\,kg\]mass is \[6\,m{{s}^{-1}}\]. The kinetic energy of the other mass is [CBSE PMT 2005]
A) 256 J
B) 486 J
C) 524 J
D) 324 J
Correct Answer:
B
Solution :
According to law of conservation of linear momentum \[{{m}_{A}}{{v}_{A}}={{m}_{B}}{{v}_{B}}\]= \[18\times 6=12\times {{v}_{B}}\]Þ \[{{v}_{B}}=9\ m/s\] K.E. of mass 12 kg, \[{{E}_{B}}=\frac{1}{2}{{m}_{B}}v_{B}^{2}\] = \[\frac{1}{2}\times 12\times {{(9)}^{2}}=486J\]