A) 20 J
B) 10 J
C) \[4\sqrt{5}\] J
D) 10\[(\sqrt{5}\]-1)J
Correct Answer: A
Solution :
At highest point velocity \[{{v}_{1}}=\sqrt{rg}\] At lowest point velocity\[{{v}_{2}}=\sqrt{5rg}\] \[\therefore \]Difference in kinetic energies \[=\frac{1}{2}m[v_{2}^{2}-v_{1}^{2}]\] \[=\frac{1}{2}m[5rg-rg]\] \[=2m(rg)\] \[=2\times 1\times 1\times 10\] \[=20J\]You need to login to perform this action.
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