A) zero
B) \[288\text{ }J\]
C) \[172.8\text{ }J\]
D) \[144\text{ }J\]
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 \[{{m}_{1}}{{u}_{1}}+{{m}_{1}}{{u}_{2}}={{m}_{1}}{{v}_{1}}+{{m}_{2}}{{v}_{2}}\] \[\Rightarrow \] \[4\times 12=(4+6)v\] \[\Rightarrow \] \[v=4.8m/s\] Kinetic energy before collision \[=\frac{1}{2}{{m}_{1}}{{u}_{1}}^{2}\] \[=\frac{1}{2}\times 4\times {{(12)}^{2}}\] \[=288J\] Kinetic energy after collision \[=\frac{1}{2}({{m}_{1}}+{{m}_{2}}){{v}^{2}}\] \[=\frac{1}{2}(10){{(4.8)}^{2}}\] \[=115.2J\] \[\therefore \] Loss in kinetic energy \[=288J-115.2J\] \[=172.8J\]You need to login to perform this action.
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