question_answer

A body of mass m is moving towards east and another body of equal mass is moving towards north. If after collision voth stick together, their P speed after collision would be :

A) \[v\]                                     

B) \[v/2\]

C) \[\sqrt{2\,v}\]                                  

D) \[v/\sqrt{2}\]

Correct Answer: D

Solution :

According to law of conservation of linear momentum \[mv\hat{i}+mv\hat{j}=2mv'\] Or           \[|2mv'|=m|v\hat{i}+v\hat{j}|\]                 \[2mv'=m\sqrt{{{v}^{2}}+{{v}^{2}}}\]                 \[v'=\frac{v\sqrt{2}}{2}=\frac{v}{\sqrt{2}}\]