A) \[-20J\]
B) \[-10J\]
C) \[-30J\]
D) \[0J\]
Correct Answer: B
Solution :
According to work energy theorem \[{{w}_{gravitational\text{ }force}}+{{w}_{air\,drag}}=\] change in KE \[\Rightarrow \] \[mg.\Delta r+{{w}_{air\,drag}}=\] change in KE \[\Rightarrow \] \[-mgh+{{w}_{air\,drag}}\] change in KE \[\Rightarrow \] \[{{w}_{air\,\,drag}}=\] change in KE + mgh \[=\left[ 0-\frac{1}{2}m{{u}^{2}} \right]+mgh\] \[=-50J+40J=-10J\]You need to login to perform this action.
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