A) -0.5J
B) -1.25J
C) 1.25J
D) 0.5J
Correct Answer: B
Solution :
Gravitational force is a conservative force apply law of energy conservation \[{{\operatorname{k}}_{A}}+{{P}_{A}}={{k}_{B}}+{{P}_{B}}\] \[\frac{1}{2}\times \frac{100\times {{\left( 5 \right)}^{2}}}{1000}+0=0+\frac{100}{1000}\times 10\times H\] \[H=\frac{25}{20}\operatorname{m}\] \[{{\operatorname{W}}_{gravity}}\,\,={{F}_{gravity}}\,\,H\,\,Cos18{{0}^{o}}\] Since \[\vec{F}\,\,\operatorname{and}\,\,\vec{H}\]are opposite in direction \[=-mgH\] \[=-\frac{100}{1000}\times 10\times \frac{25}{20}=-1.25\operatorname{J}\]You need to login to perform this action.
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