A) \[2u\]
B) \[\frac{u}{3}\]
C) \[2u\]
D) \[\frac{u}{4}\]
Correct Answer: B
Solution :
Key Idea: Momentum is conserved before and after Collision. From the principle of conservation of momentum, if no external force acts upon a system of two (or more) bodies then the total Momentum of the system remains constant. \[{{m}_{1}}{{u}_{1}}+{{m}_{2}}{{u}_{2}}={{m}_{1}}{{v}_{1}}+{{m}_{2}}{{v}_{2}}\] Given, \[{{m}_{1}}=m,\,\,{{u}_{1}}=u,\,\,{{m}_{2}}=2m,\,\,{{u}_{2}}=0\] (Stationary) \[\therefore \] \[mu+2m\times 0=mv+2mv\] \[\Rightarrow \] \[v=\frac{u}{3}\] Hence, speed of system after the collision is \[\frac{u}{3}\].You need to login to perform this action.
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