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