A) zero
B) 288 J
C) 172.8 J
D) 144 J
Correct Answer: C
Solution :
In an inelastic collision, kinetic energy is not conserved but the total energy and momentum remains conserved. Momentum before collision = Momentum after collision \[{{m}_{1}}{{u}_{1}}+{{m}_{2}}{{u}_{2}}={{m}_{1}}{{v}_{1}}+{{m}_{2}}{{v}_{2}}\] \[\Rightarrow \] \[4\times 12=(4+6)v\] \[\Rightarrow \] \[v=4.8\,m/s\] Kinetic energy before collision\[=\frac{1}{2}{{m}_{1}}u_{1}^{2}\] \[=\frac{1}{2}\times 4\times {{(12)}^{2}}\] \[=288\,J\] Kinetic energy after collision \[=\frac{1}{2}({{m}_{1}}+{{m}_{2}}){{v}^{2}}\] \[=\frac{1}{2}(10){{(4.8)}^{2}}\] \[=115.2\text{ }J\] \[\therefore \] Loss in kinetic energy\[=288\text{ }J-115.2\text{ }J\] \[=172.8J\]You need to login to perform this action.
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