A) \[60\,\,J\]
B) \[36\,\,J\]
C) \[24\,\,J\]
D) \[12\,\,J\]
Correct Answer: B
Solution :
Applying Work-Energy theorem, we can write \[\Delta W=\Delta K\] \[\Rightarrow \] \[{{W}_{t}}+{{W}_{g}}={{K}_{t}}={{K}_{i}}\] Where. \[{{W}_{f}}\] = Work done by frictional force \[{{W}_{g}}\] = Work done by gravity \[{{W}_{f}}\] = Final kinetic energy \[{{W}_{i}}\] = Initial kinetic energy \[\Rightarrow \] \[{{W}_{f}}+mg=\frac{1}{2}m{{v}^{2}}-0\] \[\Rightarrow \] \[{{W}_{f}}=\frac{1}{2}m{{v}^{2}}-mgR\] \[=\frac{1}{2}\times 3\times 16-3\times 10\times 2\] \[=24-60=-36\,J\]You need to login to perform this action.
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