A) \[Mg\]
B) \[Mg\left( 1+\frac{h}{s} \right)\]
C) \[Mg\left( \frac{1-h}{s} \right)\]
D) \[Mg{{\left( \frac{1+h}{s} \right)}^{2}}\]
Correct Answer: B
Solution :
Let F be the resistive force of wooden plank. It will be acting opposite to the weight of body therefore, resultant force opposite to motion \[=F-Mg\] Velocity of fall\[=\sqrt{2gh}\] Work done\[=(F-Mg)s=\] kinetic energy \[=\frac{1}{2}M{{(\sqrt{2gh})}^{2}}\] or \[F=\frac{Mgh}{s}+Mg\] \[=Mg\left( 1+\frac{h}{s} \right)\]You need to login to perform this action.
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